Time-shift entity-template result back in time

I’m calculating the 15-minutes peak consumption with templates.
At present, the results are time-shifted with 15 minutes because the result of the calculation is known only at the end of the period.
Is it possible to assign the result of an entity-template calculation to a time in the past (in my case 15minutes ago) ?

There is no official/supported way to do this. However there is a thread here that indicates it may be possible though I haven’t tried it yet. It’s been on my list of things to test.