https://blogs.adobe.com/creativecloud/favorite-features-in-cc-versions-of-after-effects-command-for-moving-anchor-point-to-center-of-content/?red=a

This is the thing, it used to be less than obvious to get the anchor point centred, here’s how, now:

Layer > Transform > Center Anchor Point In Layer 

You can also Ctrl+double-click (Windows) or Command+double-click the Pan Behind (Anchor Point) tool to invoke this command.

Of course look at this plugin as its very useful too:

http://www.batchframe.com/extras/info/Move%20Anchor%20Point