It does make a bit of difference. On 2% most traders would be generating more commision than paying, and vice versa with 5% comm rate. I'm calculating paid/generated commision of my bots and can simulate different commision rates. You'll have to trust me that these figures are correct or do your own excel simulations.
Scenario 5%:
gross pl 1790.92
paid comm 405.77
generated comm 297.75
PC 60.43 (1790.92 * 0.2 - 297.75)
total comm 466.2 or 26% of gross pl
Scenario 2%:
gross pl 1790.92
paid comm 162.31
generated comm 176.02
PC 182.16 (1790.92 * 0.2 - 176.02)
total comm 344.47 or 19.2% of gross pl
2% scenario you get a lot bigger PC charge, but total comm paid is 122 less