70% ft, half two shot fouls, half one and ones= 1.4 plus .7 plus .49 or 2.59 divided by 2 equals 1.24 pts per posession.
this is wrong. wrong twice, actually.
1) ratio of two shot fouls to one and ones is too low. you can have a max of 3 one and ones in a half, in reality, since many fouls are committed on shot attempts, and some fouls are non shooting (player control), you usually have less. i don't know the %s of each, but i'd guess the average is between 1 and 2 one and ones per half. probably closer to 2. i'll use 2 in the calcs below.
on the other hand, the number of 2 shot fouls is unlimited. for kstate, let's use _fan's 25 fta/game number (last year kstate had 29 fta/game), that translates to about 22 ftas from two shot fouls and approx 3 from one and ones.
2) your calcs assume that they miss the front of all one and ones. obviously that doesn't happen. at 70%, there should be 1.7 ftas per one and one. 1.19 points per one and one.
with a ratio of 2:11 (from 25 fta/game), you get 1.37 pts per possession resulting in free throws @ 70%
1.16 pts/poss @ 60%
0.96 pts/poss @ 50%
it is also relevant to mention that essentially no one shoots 50% fg, even 50% efg (weighting 3 point shots) is significantly better than average. and almost no team will shoot below 60% on fts. essentially, even teams that shoot really well from the field and really poorly from the line, obtain more points/poss on free throws than on non-ft possessions.