Not the case. The service pack can't be added to the PCP, at least not easily. It is either paid up front or deducted from your deposit.
There are rules around what can be added and although service packs can technically be added it is an insane headache, massive admin and involves the head of business approval and taking out different VAT amounts and allocating funds per bucket. Something of a nightmare.
I thought the dealer was trying to mess me about so I checked with someone I know who is a head of business at a JLR franchise and they advised me if a service pack is added to a PCP and it isn't done in the correct way they would fail an audit and lose their entire years bonus from the brand. It is. It worth it at all and if a cowboy does it discretely to get a deal in they will be fired. It isn't worth it at all so 99% of the time it comes out of the deposit or is laid up front. Either way same outcome.