Where is the amount credited to if you debit it out of service revenue under adjustments?

I figured it out... I had it wrong... if you have earned but unbilled fees, then you debit accounts receivable, and credit service revenue.

That's correct.

And you'd never debit a revenue account for an adjusting entry. A correcting entry, sure, but not an adjusting entry. The point of adjusting entries is to record revenues and expenses, not remove them.