I think I have used DU for almost every trip, at least some part of it anyway. Since we bought DVC we find we don't use DU nearly as much as we used to. But, I do like to add a few days on either end of my dvc stay (hate using those week-end points). I just sent off an email to my agent telling her that I wouldn't blame her if she started not accepting me since I always make a zillion changes to my original requests!!! She is always very goodnatured about it and has always been able to get me what I've asked for. Thanks Shirley!!!!! So, don't worry about bothering them. You should have had a spot to fill in the types of things you will be wanting to do as far as PS goes. Then when the time gets closer to the 90 day mark, your agent will be in touch to find out what you need/want.
And something odd....on my last three trips, the only PS that there were any problems with were the ones I booked myself. Things like having the name wrong, or not being able to find it or the wrong time. They all worked out fine in the end but I just found it curious that the PS that DU got for me were all fine. And yes....I copied everything down correctly. Good thing I not only call the week before I go but I carry my list of confirm. numbers with me to the restuarant!