An old beekeeper told me years ago,that if you had a strong hive and a good
flow,foundation was as good as drawn comb.I found this to be true ,but a
mistake either way with wax foundation can result in a real mess(combs
drawn on warped foundation,or foundation falling out of the frames).
 By the way,if your wax foundation is just a bit warped at the end of the
season,you can salvage it by dipping the whole frame in warm water and
patting it flat on a 3/4 inch(embedding) board.(a tip that Roy Thurber
wrote in ABJ years ago)I have had to do this on occasion and it works OK.
---Mike