Uh, no.
If you were a licensed dealer you would realize how wrong you are.
I average three "multiple sales" of handguns each week.....and i only do transfers. Storefronts in my town average three multiple sales EVERY DAY!
Each form takes about three minutes to complete...IF.....I don't get interrupted. Then I get to address an envelope to the local PD so I can mail their copy, then i get to fax a copy to ATF.
Not too much of a hassle if a customer acquires both on the same day, but if that customer comes in and I transfer another handgun.....i get to go back and fill out another form. I have one collector who picked up four pistols in a week.....none on the same day. Guess how any forms/faxes/mailings that was? (three)
If I fail to notice that the guy who bought a gun on Monday, picked up another one one on Friday I'm in violation. ATF considers each and every error or ommission as "wilfull" which could lead to a fine, imprisonment or loss of my FFL
So, yeah...the burden is minimal.