-Copying and pasting from what I wrote as a comment on 18 to 88, because that's all I have to say tonight. Might have more after some sleep and plenty of over the top Brady love tomorrow.-
52 extra passes to tie the record. It doesn't invalidate the record that Brady needed more attempts, the record is his and no one can argue that he didn't throw the most TDs in NFL history. Where the attempts comes in is in comparing Brady's season to others (2004 Manning's because few other seasons compare statistically).
49 TDs in 497 attempts vs 50 in 578 attempts.
Who threw more TDs? Brady, obviously.
Who had the better season? I'd say Manning. A TD on average every 10 attempts for Manning compared to 11.5 for Brady. Almost a yard more per attempt (.9). 1.6 more yards per completion.
If Manning had the number of attempts Brady had this season (not much of a stretch because Manning was pulled earlier and more often from blowouts)...
04 Manning with 578 attempts
57 TDs, 5317.6 yards, 11.6 INTs
04 Manning with 526 attempts (Manning takes all of Sorgi's 04 snaps)
51.9 TDs, 4822.9 yards, 10.6 INTs
2 more TDs, 17 more yards and 2.6 more INTs.
Manning could have crushed the TD (and passing yards) record if he played as late into blowouts and the season as Brady did.