Incremental Effect of Win % Picking ATS

It's generally known that in order to break even picking games against the spread, you need to maintain a win percentage of 52.38% (with the standard -110 line). Also, it's incredibly hard to do: which is why even the best in the world only hit 54-55% of their bets:

.@_Tank6_ Much better off going for 54% on a large number of plays.

— Haralabos Voulgaris (@haralabob) December 21, 2015

My goal has always been 55%, which still means you're losing 4 out of every 9 bets you make. However, you should never try to stop improving: my current win rate sits at 54.9%, but I'm still chasing the holy grail: 60%.

How much of a difference is there between those 5 points? I wrote a quick simulator in Python to estimate the average ROI, when compounding your bankroll after each bet, for each 1 point increase from 53% to 60% (over 1,000 bets). This is pretty simplistic, but over 10,000 simulations the outliers should be smoothed out enough to get an idea of the big picture. And the results are (predictably) exponential:

Win %	ROI	x Over
52.5%	2.90%	0.04
53%	13.2%	0.20
54%	36.5%	0.55
55%	66.2%	1.00
56%	99.2%	1.50
57%	243.6%	3.68
58%	294.4%	4.45
59%	356.0%	5.38
60%	429.2%	6.48

60% is worth almost 6.5x MORE than 55% (over 1,000 bets). In graph form:

Never stop chasing 60.