Can you use Izotope Ozone more than once in Pro Tools?

I asked a guy if you can use Izotope Ozone multiple times for multiple tracks in Protools, like one for a guitar track, and one for vocals, and maybe another with a different setting for a different sounding guitar track. The guy i talked to said no, as it is just a mastering software and should only be used once. He also said that i should use other VST's to edit my guitar sounds before mastering it with Izotope. I know its for mastering, but i like how it has different settings for guitar and vocals, which is why i wanna use it more than once. The guy said that i shouldnt because i would overcompress or make the song sound weird because of all the frequencies being changed or something like that? Is that true? If so, should i just try to edit my tracks with the good old compressor or whatever, depending if their vocal or guitar or what?