Why do you keep calling these sales pre sales? They are closed sales sold from the builder's office. I argue here frequently that in a new construction appraisal that to develop credibly supported MV, appraisers should use at least two re sale comps (meaning properties not sold through builders office), , and analyze the resale market, not just use all new from builder sales. That said, I do believe new home sales from builders are also god comps and in many cases necessary to develop th eMV, and see if the market is paying the premium builders charge or an equivalence after adjusting for C 1 .
I therefore typically in a new home appraisal include at least 2 of what you call "pre sales", aka sales from a builder's office. Which is not the same as saying their price is the market value, it may or may not be, but they are still viable comps .
As far as open market exposure, builder sales may not have the same exposure as resales from private owners, builder sales do have open market exposure. While the date on MLS might a 0 or 1 for DOM, ( date to contract), these homes were available on the open market prior to that during the time the builder sales office was open.
I am surprised to see that in your reviews you never see appraisers use new home sales from builders... ( unless by pre sale you mean something else)