With the caveat that Disney can change prices whenever they please........
Historically they have raised the price of admission tickets in August the last couple of years. And there is usually VERY little notice of it....for example in 2007 they announced on Friday that the rates would increase on Sunday, so you basically had Fri/Sat to scramble and buy at the lower rate. The raise in price for a 10 day was about $25 I believe, so it's not huge, but multiply that by a family and it's a bigger difference.
Free dining has been offered late August/most of September for several years now. No one knows if they'll do it next year of course. Historically the have announced it in April, with Disney VISA holders getting first dibs for a week or so before it's open to the general public. I can't recall if AP holders got advance booking too??
The "catch" for the free dining is that you have to purchase at least a one day ticket for everyone in your family. Last year, they changed that for AP holders, which was nice because a 1 day ticket that you don't need is a waste of money, lol. AND, the bigger financial "catch" is that you have to pay RACK RATE for the hotel room. You cannot get an AP,
AAA, Disney Visa or any other discount and also get the free dining. These sell out quickly, so if you want to do it, I'd suggest you start watching DIS in mid-March as they usually have rumors about when it will open for sale.
Some things to consider....free food sounds wonderful, and for a family of 6 it's likely to be a good deal.....but you will have to rent TWO resort rooms in value, moderate and most of the deluxes, because they only allow 4 people in most of the rooms, 5 in some of the value suites (which of course are more expensive). I believe the only rooms that can accomodate 6 all together are the deluxe suites and the cabins (and I can't recall if the cabins get free dining, I know the campgrounds don't). This are of course quite expensive at rack rate.....but there are often deals on these more expensive rooms at other times of the year. Staying off site with a large family can be even more cost effective, not to mention having more space! The other major downside to free dining period, whether you get free dining or not, is the crowd level is at one of the highest levels except for holidays. This means that the trade off is longer lines, less rides you'll be able to get on, and crowded restaurants (if you do sign up for free dining, get your ADRs made at exactly 180 days as these fill up really really fast, even the less popular restaurants book up quickly).
What you might want to do is sit down and do some calculating.....what would it cost you to stay offsite (if this is an option you want to consider)....you'd need a car to get to Disney each day, but you can save money by eating 1 or more meals at home, and you'll have a lot more space, amenities and often a private pool. Then figure what it would cost to stay onsite at a different time when you can get a discount (Visa, AAA, AP, etc). If you knew the lines were going to be longer would you stay longer so you can get done all that you want to do? This might mean going non-free dining times you could stay less days and still get the same things done, so that's cheaper too.
Then go to allearsnet.com/menu/menus.htm and look through the menus and decide where you'll want to eat each day (you'll need to do this for free dining to prepare for your ADRs too). Then calculate the cost of what everyone 'might' order. Add this to your discounted hotel or condo/home rate to see if you'll save money. Many people have found that after considering that they'll need to stay a few extra days for free dining period that they cost savings is only a couple hundred dollars. And that it's not worth the small amount of savings to stand in long hot lines. Every family of course will have differing opinions on this. You'd never get me to go during free dining, even if they offered a discounted room rate.....those types of crowds are definitely not my thing.
You've got some time to make some decisions. If you're going to try for free dining, I wouldn't buy those tickets from your employer because that $40 savings would be offset by the requirement that you buy at least a 1 day ticket for everyone in your family, which is usually about $70. You could buy from your employer with 1 less day, but you'll still have to pay the $70 for that 1 day ticket so your net savings will only be about $10-15 (once you get over 4 days adding additional days is a couple dollars a day). If you are planning to stay more than 12 days, most agree that an AP is the best price, or if you plan to return within 12 months (many stagger their vacations each year so they go in August this year and get an AP, and then go next year in July before their AP expires to get a second use out of it). If you don't want to wait and see about free dining, then you might go ahead and buy the tickets from your employer now....not only is it a savings of $40 (and these tickets are rarely discounted much....undercovertourist.com is about the largest discount consistently available, their price includes tax, so compare that with your employers cost once you know if employer includes tax or not). Your tickets don't expire until 14 days after you first use them, so buying it now means you can save it until next year (or even the year after that, etc), and not only save that $40, but also any price increase that will likely happen next month, and then again next August perhaps before you arrive! If you would be charging these tickets in advance and paying finance charges it might negate the savings, so it may be wiser to simply put a little away each month until you go as though you were making the payments, but without the finance charges and buy it next summer before 2009 increase hits.
Lots to think about, but if you truly want to save as much as possible, you'll have to put in some time crunching numbers to find out what works best for your family.
Have fun!