Furnace filters

I have to say the whole subject of finding replacement furnace filters has been very frustrating! I went to Lowe's and bought a very nice, 12 month, Filtrete Allergen 16" x25" x 4" replacement filter.  I brought it home and it didn't fit.  So, I looked at the original filter and looked at the measurements a little more closely.  Why in the world, do they have 16" x 25" x 4" on the filter when those are not the correct measurements! The correct ones are 15 3/8 x 24 3/8" x 3 3/4" and yes those do make a difference in a filter fitting! So, I went to return the Filtrete filter to Lowe's and went to the Home Depot and same story there.  I finally decided just to check AAF's website and their web store didn't even carry the filter.  I then decided to email AAF and they said the nearest AAF rep was in Columbus.  I then turned to Google and found a company here in Dayton, BDI, that was willing to special order the filters for me at a very good price.  FYI, these filters come in a case of 6.