About half of the builders don't not put any sales in the MLS. For the ones that do, I still call and verify. Most are presales are put in as for comps only.
The issue is that our MLS has a policy with presales and the builders do not put in the actual contract date due to the MLS rules.
As for non MLS new homes, I contact the builder and get the data....contract date, sc, upgrades, lot premium, etc.
As for adjustments, I ask how they are adjusting the base prices. Monthly, quarterly, etc.
I also get the base prices for comps and for older sales from the pud, even though I may not use them. I then compare what the base prices currently are.
I try to get a print off of the summary page. The builder may be keeping the base prices stable or are increasing them, but are offering free upgrades, incentives or seller conessions....they try not to **** of prior owners by lowering the base price.
As others have said, most presales have contract dates +_6 months. Therefore you have to verify with the builder.
When I can't, I have a trick...pull the permit. It is usually on or 1 month prior/1 month after. Of course if it is a builder spec and the contract was signed during the construction phase, the permit date trick want help.
If you use alamode, use their comp sharing feature. What stinks, is that if they are not in the MLS....appraisers will not use them, therefore they will not be in alamodes comp sharing data base. They only use the builders cherry picked MLS sales. Sad.