I've used excel for absolute donkeys years, don't consider myself an expert and perhaps some of my formula could be better written - especially where multiple formula within the one cell is deployed, I have lots of hidden columns and also created an index list - so when amending I can look up which hidden column i need to access without having to reveal all, but everything works perfectly.
Time to upgrade your skills to Database Programmer. Its a better solution (if you fancy it) than Excel Formulae, because the data is the data, and you can apply "program stuff" to it. Modify the program-stuff until it works correctly. If you find a bug then modify it some more (but your data is still separate, and you still have your Version One program-stuff until such time as you are happy with Version Two and then bin V1.
And you can also QUERY the data - "how many days did we generate more than X kWh, and on those days what proportion was AM / PM" ... and so on.
You can do all that with data in XLS but its a) blinking hard and b) very error prone.
Excel : Lean on keyboard and you've changed the data in a cell, and you'll never know it.
Database: Yeah, you can bulk change the data wrongly too, but you will have backups and, if you want, an Audit of all previous values for that record - so you can use that to find out What / Why / When it broke.
perhaps some of my formula could be better written
Reminds me of a client of mine, donkeys years, ago.
"Can you look at my spreadsheet?"
"Sure"
"When I press CALCULATE ..." (this was back in the days when you had to do that, before "real time") "... I get this '
Circular Formula' message"
His spreadsheet was EVERYTHING in his company. All the individual sales, all the wages, all the timesheets. He was proud of how proud his bank was of his forecasts
I explain what a "Circular Formula" is ... and then:
"Try this: Scroll down to the Bottom Line. See the PROFIT figure at the bottom?"
"Yes"
"Press CALCAULTE"
"Oh, the PROFIT has changed"
"Yup, ok press CALCULATE again"
"Hmmm ... the PROFIT has changed again"
"Yup"
6 months later I was in his office, he went for a pee, his spreadhseet was open. I scrolled to PROFIT and pressed CALCULATE ... Yup, I got a new figure.
Too hard to fix.