Was I over charged for a new shower in my apartment?

[Dana Revallo]

I just had a leaky shower replaced in a 4 plex.  I have a new plumber and am new to this and wanted to see if I was overcharged.  I am an out of state investor and the property is in Michigan.  Plumber removed old shower and had a contractor move the drain and repair rot in the floor.  Plumber installed new delta shower valve and installed shower.  Contractor installed shelves. I've included photos.  Total cost was about $4700

He's done great work so far,  I just want to make sure I'm not getting the "California tax" 

Old shower