Zero Turn Mowers

I have a Husqvarna MZT61 zero turn mower. It is time to change the transmission fluid on the hydrogear transmissions. I have purchased the filters and fluid. However, I have talked to two Husqvarna authorized dealers and both of them told me to not change the fluid. They said they don't do it. They said it is too hard and that I will never get all the air purged out. They said I will start having problems. My questions are: Should I go ahead and do it? Is it really that hard? Will it start causing problems?