1. The storage requirements for Pfizer and Moderna were known many months ago. Storage at dry ice temperature (Pfizer) is not that exotic, since dry ice can be purchased at ordinary grocery stores. Moderna's storage temperature is in the same range as an ordinary home freezer.
2. The Pfizer, Moderna, and other three vaccine vendors' purchase contracts are for fixed numbers of doses at a fixed price (in the cases of AZ, J & J, and Novavax, their contracts go into effect if/when they receive Emergency Use Authorization). Wastage has no effect on those contracts unless it becomes extreme that an extra option (fixed quantity and price) has to be exercised.