1995 lexus es300 remote start

I had a company install a Automate AM6 remote start system in my Fiance's 1995 Lexus Es300 car.

When they were done,  I noticed that when you remote start the vehicle and get in (vehicle running),  when you turn the key on,  if you go to far, the starter will grind.      They tell me that this cannot be changed due to it being a 1995.    I said that the starter motor should be disabled while the remote start is active so you don't grind the starter when turning the key on,   am I wrong?    What did they do wrong?

Also, the feature of activating the rear defroster does not work,   and they say this also cannot be done in this vehicle??????

I really wanted the AM7 to be installed with the full blow security system, but they say it won't work well with the factory alarm that is built in to the car already???

Please help.