Heating switches. timing T delta before switching on


I recently got a Gen 2,

reading the manual it states to use only 500W during the mash.
but when doing that i noticed my temp dropped about 2 degree C.

I started suspecting an issue, so carried on with just the 1900W. all good

going to the boil I flicked the 500W back on and noticed it kicking in very late (indicated by the switch lighting up) about 2 seconds after temp increase, where the 1900W kicked in as soon as i raised the temp.

Is there a deliberate delay in the 500W circuit? and what is the delta T expected when operating on only 500W?