Because it's
5.1p/unit + 25.3p standing gas
21.3p/unit + 23.6p standing for electricity
For me today:
4.9p/unit + 26.84p SC for gas
19.51p/unit + 37.3p SC for electricity
Been around these prices for a while now too.
I probably would not risk moving from your fixed rate either to be fair. Forgot your fix was that long.