Usually, the fuser web is due at the same time as the K drum, as its on the same 150K counter. When you change the K drum unit, you are going to have to check all counters in 22-1 and 22-13 to make sure nothing else is due or near-due. Make sure the firmware is up-to-date.
Are you familiar with Sharp machines? Is this your only Sharp machine? You should be getting yourself the service manual, as there is alot more to these machines than just replacing something & resetting it.