Question HDDScan results


I've been testing a refurbished 3TB HDD I bought to run in mirror, with an identical drive I already have, in a NAS (Using FreeNAS). Using HDDScan because I've been told that smart information can be erased. I've been running butterfly test for 21 hours, at time of writing this, and it's still at 61%. I'm just wondering if the results so far are alright. The drive is a 3TB 7200RPM HGST drive, which I believe was made in 2013-14. It's amazon renewed, and they apparently did their own testing, but I decided to do my own for obvious reasons.

Here are the S.M.A.R.T and Butterfly test results: View:

Looks like there are a lot of <500ms parts. Also, the drive speed is increasing, rather than decreasing, which seems unusual, although it is fairly consistent. Anything to worry about here so far?