Encryption time remaining keeps changing?

This may be a really stupid question but I'm just curious, is there a problem when the "__ (hours) remaining" estimation for FireVault encryption keeps changing drastically? Like I wouldn't think twice if it was going back and forth from like 45 to 40 to 42 minutes, but it keeps going from 1 hour to 13 hours to 14 hours to 2 hours then back to 1 hour and then back to 5 hours, etc., etc., with more random numbers. While I was typing that previous sentence on my phone it went from "more than a day remaining" to 22 hours, and now it's at 13 hours again. I was wondering if maybe I had to give it a simple fix like closing out of settings and reopening it, or if it was just the estimation process malfuctioning, I don't know.

EDIT: I did clear a significant amount of space (there was only 128 GB free before and now there's 332 GB free) while the encryption was taking place, would that have anything to do with it making bad and random estimates?