I see most good players use a 1/3 cbet in spots when they are betting their whole range, however I spent a lot of time on Piosolver (with rake) and 1/4 is actually almost always yielding more EV when betting range in spots when you want to cbet small (usually very small difference like 0.1-0.2% pot, but on some boards it's up to 1% pot).
When cbetting range the strategy doesn't get any more simple for us so even though the difference in EV is very small I feel like it should be logical to choose the sizing worth more EV, but the good players use the other one.
Does anyone know why? Is there an advantage to choosing 1/3 that makes up for the difference? Probably sounds like a worthless question but since cbetting range spots happen very often that feels important.
Thank you for reading, any answer/thoughts would be appreciated.