I'm getting less miles in several levels

You can read what Queen Mia wrote about this here:  https://community.king.com/en/bubble-witch-saga/discussion/246404/level-changing-not-getting-the-same-amount-of-moves-as-your-friends-or-as-on-videos#latest

If you see videos online showing more moves, this is the reason.  The videos are outdated because the video creators make them when the levels are first released.  The studio monitors all levels when they are released and they check to see how many players clear a specific level and how long it takes for them to clear it.  If it's too easy or too difficult they will "tweak" the levels a bit.  The video creators can't keep up with the studio changes so you are still only seeing the first video release.