The real problem here is that people keep trying to screw up the simple thing.

If you want to know the timestamp of "two days from now" then you need to know all kinds of things like what time zone you're talking about and if there are any leap seconds etc. That would tell you if "two days from now" is in 172800 seconds or 172801 seconds or 169201 or 176400 etc.

But the seconds-counting thing should be doing absolutely nothing other than counting seconds and doing otherwise is crazy. The conversion from that into calendar dates and so on is for a separate library which is aware of all these contextual things that allow it to do the conversion. What we do not need and should not have is for the seconds counting thing to contain two identical timestamps that refer to two independent points in time. It should just count seconds.