"My only concern is whether there are check measures in place that carefully regulate the billings that TPL (Alliacense) charges PDS so as to guard against any shenanigans."

I understand your concern, but would point out that there was something in the latest 10k that made me believe that these expenses are in fact watched carefully. Something about PTSC having a receivable from pds or tpl for expenses billed that were not allocable to ptsc. Sorry I can't be more specific but I don't feel like finding the blurb right now.