Muddy, this is where someone like myself and a "Pro" (in quotes not to disrespect but to draw attention that not all considered Pro's consider themselves Pro's but may be precieved by others as Pro's) differ, not in terms of expectations and ROI but just general philosophy.
The program I designed and use isn't like a model or a system or anything that Think Tankers would maybe even acknowledge. Basically what it does is give me a calculated line. From that point I have a "must meet" variable that the calculated line must surpass. This narrows the field and allows me to focus on specific games that have met the requirements. Now I have judged "my program" based purely on it's generated numbers and it's right around 53% give or take a couple of decimal points for the past 2 seasons. I can't afford to spread myself out like that across the board so I take what lines are off by the most and research them from that point forward to come up with my final card.
Guys who do this for a living would probably take 53% across the board but a recreational player with recreational funds has to limit the number of plays.
Also to further the point. Someone in my position (who thinks like me, which absolutely doesn't mean it's logical outside my own head) tries to estimate the value of each play he/she is wagering on as equal value. Not in terms of line prices but just general terms of chances to win. So someone like myself does focus on win% over +EV vs -EV because if my %'s stay high my returns match. In order to think like a "Pro" I would have to work much harder, dedicate much more time and lose much of the enjoyment of the games themselves.
I am sure many will not read any of this and of those that do read it, won't agree. That's cool but if you don't understand my way of thinking or have imput to make me adjust some if not all (all is doubtful) please chime in. Even if I don't change my style it could be of value to someone else.