As people said, the web GUI is faulty. HEC actually applies to ATM, and doesn't matter to FTTC - and the number that is displayed is actually more likely to be a badly-displayed negative number (-6, to be exact). In programming parlance, it is a 32-bit signed number being displayed as though it is 32-bit unsigned.
The sync looks fine, with G.INP enabled.
The error rate looks fine too, but there's only 20 minutes of data, so it is too soon to be sure.