Battery Sony Infolithium

Battery Sony Infolithium
Sony Infolithium P instead of H on DVD308?

My uncle an I will be taking a trip together. My camcorder uses P series batteries and his uses H series. I know that Sony replaced the P series with the H. My 2006 camcorder can use the new P series batteries according to the website.

Does anyone know if the reverse is true? I would like to use my NP-FP71 on his camcorder since we will be taking his on the trip.

From what I read in this discussion thread, the older NP batteries cannot be used in the new Sony camcorders that uses the new NH batteries.
http://www.camcorderinfo.com/bbs/t136180.html

Replacement 7.20V 1450mah Digital Camera Battery NP-FM50 for SONY infolithium M