Hi, this is my first post ever. Please allow me to try and interpret what the OP is requesting:
Buy-in = 0.3 pts per player
Ranks (places of finish...I get this variable mixed up with Position) (ie: 11th-15th place) = 0.3 x number of players who bought into the tournament
[Example: if 50 players bought-in to the tournament, then Places 11th - 15th will earn 0.3pts x 50 = 15 pts each...although the OP indicated "1.5" in the example]
Ranks 1st-10th place = 0.36 x number of players who bought into the tournament
Essentially, I believe the OP is trying to setup the Top-15 players to be considered as ITM ("In The Money").
Ranks 1-10 will have (0.36 x number of players) + (0.3 for the buy-in)
Ranks 11-15 will have (0.3 x number of players) + (0.3 for the buy-in)
I hope I've interpreted this correctly and that my explanation makes sense (and not cause further confusion).
Thank you and good luck.
-Al