I am almost positive there has been a merchant service like this in the past that worked for spell-based x/day at least, but I have not seen it offered for a while.
#Convert Items to New-Style x/day
odd ibex
brittle sentinel
There are a whole host of systems that use 22 hours as the timer instead of 24 (REIM as an example).
It feels like adjust to a 22 hour timer could make a lost of sense, if true x/day resetting at midnight isn't an option.
odd ibex
I've silently hoped for something like what you are noting Kontii to become standard for x/day to manage slight variations in playtime.
midnight onyx
Convert Items to New-Style x/day