I agree with J0hn re Retx values. If you really want to check, you should telnet into Draytek. I can't remember the CLI command (currently using Fritz!box), but it's something like 'vdsl status', where you'll get the accurate values for your connection.
It's true that the upstream CRC/ES don't reset, but in some cases are an accumulative value of all CRC/ES for this particular connection since the your broadband connection was started (i.e. your contract).
You're not saying what Draytek you have. Depending on what firmware you use, you can get better/worse stats.
Also, on 2762ac, if you upload MDM2 firmware, which doesn't support vectoring, downstream and upstream values are reversed for some reason (in comparison to STD, MDM1 and MDM3 firmware). Draytek Support said it was meant to be that way. BT firmware is, as far as I remember, the same as MDM1. Or, rather, MDM1 is repackaged as BT firmware. MDM3 is most conservative of them all and works best on problematic lines.