Convert Time to Decimal with Custom Time Matrix

Hello again, I've been using the formula and everything was good until someone found an anomaly. When I go through the times and check the formula it works as advertised. However, someone found that depending on the start time used, it skews the result by .1 - However, it's not predictable and makes the spreadsheet completely unreliable. To make matters worse, I had to move the spreadsheet to Google Sheets using the same formulas and it has the same problems. I sanitized the spreadsheet and cant figure out how to post it here for review and help.