Having read both threads on this issue there is a lot of good information being provided. The swelling of the packs is quite normal if you draw the maximum permitted C rating of the pack. Having experience in LiPo packs has shown that if the discharge current is over 50% of the maximum C rating they will swell and get very hot. I am sure that these issues were considered in Mr B's design, at the same the start upn surge current from any motor whether AC or DC is considerably more than the constant current and this is not going to help these packs survive a sensible reliable life if it is greater than the rated pack C. The pack also loses its storage capacity over time if this continually done.
One hopes that Mr. B has done all the calculations and checks on the discharge of the battery packs.