I don't look on VMware very often (since I lost my semi-admin rights and hence can't configure new LUNs for them anymore
) but generally most systems are rather lazy in the use of TB/TiB. I've seen tools/software on a single OS use both but only say "GB" so the only way to be sure is to look at the total size of the LUNs in that particular tool and just hope that it's consistent in that one tool at least.
I'm guessing you're using some VMware costing addon, I'd hope at least it would clarify which in the help docs if it's meant to be used for charging.
Obviously used space is pointless as never the same between guest OS/VMware/LUN/raw, so can't really compare direct. We tend to lump all the differences under the term of VM Tax and add about 10% extra to charged LUNs for free if not RDM (we're moving away from these) however we almost never charge for 3PAR as no one here can afford it but do have other cheaper arrays for 'customers' needing TiBs of data (we are a Uni).