you really need one person unless you are asking them to coordinate with each other and that takes time for which you will be billed- twice- once for each provider.

I think they would limit on number of sessions and frequency not number of providers especially if the second is OON. At least that is my own experience. I've never tried to do two at once. In the past we've had plans which were more generous with PT since that seemed more "medical" so no pre-authorization and currently we have a plan that requires no pre-auth for speech but does for OT. IT all depends. I would hit up your benefits person for a concrete answer.

I think it depends on your insurance. I would switch to a provider who can give you the appointments so you have one stable provider.

My DC has Speech once a week with Provider A, covered by insurance (this practice has very limited availability) and I am planning to get an extra speech session with Provider B. Insurance company said that we couldn't use two providers for the same service within the same period. Pre-authorization won't be given to Provider B unless we cancel Provider A. Is this true?

Is it the same rule for OT and PT which doesn't require authorization? Same rule for out-of-network providers?

Yes, I called our insurance rep, but you know, sometimes they give you a wrong information or misinterpret the policy.