Nuova Simonelli Mythos 1 Issue

I’m a new-ish barista working in a chain shop. We use a Mythos 1 and recently we brought down a new grinder, the company sent someone to have a look at it and make sure it was running as it should.

I’ll dial in the machines every morning, using 18g dose, 36g yield, 25-30seconds run time, however since we had someone look at the machine the doses have been so irregular dialing in is getting so difficult. I’ll weigh it once, 18.8g, the next dose will go down to 18.4g by moving the dose time down, I’ll remove another 15 seconds or so and the dose will somehow go up to 19.2g and so on. The grinder has the front panel taken off and the burrs brushed out every other night but that doesnt seem to be helping at all?

Any suggestions?

Hi, I am using Mythos One too and all I can think of:
is it heating/cooling?
are the burrs aligned properly?
maybe worn out burrs?
or, Mythos have small declumping plastic thingy and if it is old it can keep small clumps of coffee inside and that can affect your dose by small amounts.

The fans are working well, theres a cool air flow coming out of them. I’ll have to check if the burrs are correctly alligned, they may also be worn. The declumping thing always gets clumps caught in it.