It's a pain - having recently been asked about buying some Office seats, I started digging into the options.
One company was selling "3 license packs" of Office 2013. That would do fine, two of those will cover this small business! Except it seems that's actually a single-user 3-PC pack, dishonestly labelled by the seller.
So, we need to buy separate licenses. (There are genuine multi-license packs, but those are for bigger companies it seems.) Pro? Business? Muggle? With or without cherry on top? A dozen different permutations from different companies at different prices - why, when the "product" is essentially a password from Microsoft giving us permission to use their software?
MS would actually be doing us all a huge favour if they simply deleted the whole "reseller" concept for retail software. Stick it all online, guarantee (like some hotels do) the official store has the best prices (easy to do: charge all customers the same per seat, whether reselling or not). It may be different for "corporate" purchases with hand-holding, but when the entire "value added" consists of stuffing a DVD in a Jiffy bag, there is something wrong.
We ended up with two seats of Office 365 (direct from MS) and two copies of Office Home+Business (from somewhere on Amazon), IIRC.