I'm not sure I'm understanding your question. To get any sort of discount at Hojo, you have to ask for that rate. The retro rates when available can be booked by anyone who asks for them; you don't have to be a senior. To get the retro rate, you have to enter the appropriate code on the website (I think it's LKEP with entertainment card and LKAP with AP card) or ask for the retro rate when booking with in-house reservations by phone. If you don't ask for any special rate or enter any special booking code, you're always going to get offered what they call
"best available rate" which I consider a pretty generic, meaningless term when looking at hotel bookings.
Hojo's standard discount for seniors is only 10% off as shown here:
http://www.boards.hojoanaheim.com/viewtopic.php?f=19&t=30
You can do better by asking for the entertainment rate (15% off when retro rates are not available, must have entertainment card at check-in), AP rate (20% off when retro rates are not available, must have AP card), or DisBoards discount (15% off, just ask for the DisBoards discount when booking), or the discounts offered by other Disney fan boards (usually 15% off like the DisBoards one).