Question about *2 update to my phone with custom rom

[xxxjdoggxxx]

I called Sprint today (*2) because I have a poor signal at home and I was trying to get a free airave (which I was successful in doing). The rep told me to hang up and call *2 again and my phone's software would update. I called *2 and a message came up on my phone saying "updating software" and I hung up right away. My question is should I avoid doing this with a custom rom on my phone?