That's exactly the core problem: what's the way to ensure that the difference in the 5-7+th digit does not lead to a 1 min shift in Zorro?
What 'smart' algos/heuristics are employed by Multicharts, SC, pandas, NinjaTrader, Metatrader, Excel, etc that such a problem just does not exist?

I regularly have to double-check that the prices loaded from a csv file (exported from Multicharts/IB) are correctly timestamped in a t6 file and then 'candles' are built correctly by Zorro.

But in this particular case:
- History Editor shows all 1-min prices with correct timestamps (as they are received from IB and are displayed in MC and in excel)
- the last/previous bars on Fri/earlier are built by Zorro correctly

- from the first bar on Sun 1-min bars are aggregated into 5-min bars incorrectly.