The $150 service call fee (SCF) is just for the tech to show up to figure out what's wrong with the appliance and it will go towards the repair cost of the appliance if they decide to proceed with the repair. (note: the fee gets applied to the overall repair cost, it doesn't get waived)
It is $150 SCF for each appliance. If they choose not to proceed with the repair and decide to buy a new appliance, $150 SCF will be charged regardless.