Giving >1 patent attorney/agent NOT from same firm POA on the SAME application

[En-trance]

I would like to find out what your thoughts are regarding whether it is fine for more than one patent attorney/agent, not working for the same firm, to be given power of attorney for the same patent application. Reading the sentence below (cut and pasted from the MPEP), there does not seem to be any rule that prohibits this, as long as the (10 or fewer patent attorneys and/or agents) are registered practitioners:   

"Powers of attorney naming joint inventors, one or more registered individuals, or all registered practitioners associated with a Customer Number, may be made. See MPEP § 403 for Customer Number practice."

[ChrisWhewell]

Canons of practice contain additional rules.   If a conflicts check passes both firms, sure, why not.   Then again, why ?

[En-trance]

Canons of practice contain additional rules.   If a conflicts check passes both firms, sure, why not.   Then again, why ?

Thanks for your comment Chris. I guess this is more of a scenario for practices in Asia, where it is more common for an US patent agent/attorney to take on (help out with) cases from another firm when there is overloading of workload.