Mary,
Believe it or not, you will find in new home sales that what you're experiencing occurs on a random basis...well...when the big boys at the regional or national builder need to make the quarterly sales quota, they will give concessions to move the unit. Just like GM and Ford. Plus, those division sales managers want their end of the year bonus. That is the most important thing to them.
I love the ones I work for up here. Once they make the quota for the year, they'll will try like hell to delay November and December closings so they can use them to meet the next year's quota in January. If they add the closings to this year's quota, the main office will up the quota for next year so they delay closings and discount the units. I've seen homes that are complete just sitting there in December waiting until January to close. Or, if they are behind on their quota, which means they are likely to get fired by the main office for not meeting their quota, they will offer you a discount to close early. It seems to be a "unit" thing rather than a profit thing. Of course, then you have the builders that don't have a clue about market value. They are told by the main office what profit percentage they have to bring back on land and building and they just add that to the cost to build and price the home accordingly. If that's all the main office expects and they can sell below market value, they get to meet their quota very easily.. and they get their bonuses.
These guys never seem to learn that when they give a fast close or delayed close sales concession that reduces the sale price to make their bonuses, that it will come back to bite them when these same sales are used by the unsuspecting appraiser as comps...which is why FNMA/FHLMC want you to analyze sales from outside the subdivision..so you can see the affect of the sales concession and explain it.
Cruise through the option sheets sometimes and you will see things like "quick close discount" ,etc. Delayed close discounts are often disguised as major free option giveaways: free finished basements, free family rooms, free fireplaces, etc. They wouldn't want it to be too obvious to the main office that they were pushing closings off to the next year, would they????
Ben