MY TAKE ONLY......
I assume THAT MOST PLAYERS who are recreational gamblers will bet $100 a game as a 1 unit play on the average.
With that in mind, a SINGLE game best bet from me, which is usually how I roll during NBA, MLB and NCAA Hoops with daily plays(not talking football at all here because 75% of the time I have mulitple game packages), that 15% for an investment charge ($15 per single play) is plenty.
Now I get emails from time to time where some people PERCIEVE that the value and or strength of a play that is warranted in their mind is based on the offering price of a selection. IT IS NOT. A $50 singled out best bet from one capper is no different than a $15 play from another, that is just his decision to price it accordingly.
When I have a 2 star or 3 star play, stronger in units and strength, my players will double or triple their bet and my price increases just alittle for those. Actually the 15% investment goes down as the amount of monies to be wagered and hopefully won goes up. Say $20 max.....I have never charged more than $25 for a single play on THIS SITE ever.
3 Game cards are usually $28 in football, or less than $10 each or in value of invesment, so you have less than a 10% investment in each play if you are a $100 player.
Each capper has his own audience and or following, and they price it accordingly.
Just my thoughts....there is no right or wrong answer.