HMRC - Credits and 1116

I’d be interested to know how others report HMRC tax paid on the 1116, (not talking of the baskets here, but the general idea). Logically whatever the total HMRC tax paid in a calendar year is what’s stated on the 1116’s. But then you have HMRC balancing payments, payments on account and credits for the previous tax year. Not a refund, maybe not even a credit that is yours to ‘cash out’, but HMRC accounting and bookkeeping?   
If you pay more tax to HMRC in one year, (higher income) and then your income is much less in the next year, you’d then get a credit that is applied to the next bill, (perhaps in the next calendar year), also a lower tax assessment too.
So, report what you physically pay HMRC in the calendar year, or treat the credit as a refund and file a 1040X. It would seem however the latter would be like trying to hit a moving target with 1040X’s going out every year?

For me it comes down to line 7 of 1116 and selecting on the tick box, paid or accrued. I take the paid route - using the accrued route is just a little too taxing on my brain (excuse the pun  )

if you take the paid route, there's no need for a 1040X.