good question and one i have had several answers to myself
tracks like phillip mitchel im so happy , luther dont wanna be a fool , collins and collins top of the stairs are all much cheaper on the lps than the 45s and often found in better condition , is it alright to play these tracks out at soul nights from lps as they still are origionals.
also nolan porter is half the price on the lp than the 45 , and demand for the 7" has put the price up whilst the lp has stayed about the same money