Cost estimation is way off

Hi there, ABRP seems to get the distance right, and the mi/kwh right, but the cost for trips is just way off (sometimes it ends up being 3x+ what ABRP things it will be) it's my understanding that rates that the chargers, well, charge may but be data that is easily available, but if that's the case, could we enter an approximate rate ourselves? What's value is it using now?