Calling oven users

[Kevdog]

Evening all,
I decided to go for a small fan assisted oven to which I also got a oven thermometer.
I have done a couple of mugs and they seem ok "though I'm still not sure about the colours from the print" but I'm finding when I finally get the temp correct I then insert a mug and the temp drops about 10 deg.

Is this normal? or is my oven maybe not up to the job?

[ArferMo]

only 10 degree drop is good.