For me, the only one who has ever used the standard terms as a floor has been the employer. The union has always backed me up when I wanted higher pay.

I'll give an example. I've had managers switched on me, and they've then said my salary has to be reduced because it's higher than the median. The organisation I work for also has a salary policy where every level you advance, your "personal additional percentage" is cut. This eventually reduces everyone to the same, lower level. This is the employer, not the union.

The union, otoh, backed me up when I wanted to keep my existing extra percentage.