How to list utilities in lease during transition

[Arron Achey]

Hello all,

Quick preface to question, I have a current tenant who wants to renew and I would like to renew her as well. I have a current duplex running on one electrical panel and looking to have it split as previous tenants have had complaints due to splitting electric evenly when usage wasn't even.  Previous owner paid some of utilities for tenants up to a cap so they definitely ran it up. Earliest someone can come out is early February and this is when the tenants lease is up.

Question is how would you structure the lease, specifically utilities, when the electric may not be officially split come time of renewal?  I'm still splitting water evenly, gas just on one unit as the other doesn't use any, but electric I'm stuck on finding the right verbiage. Maybe I'm overthinking it, either way any input is appreciated thanks!