I dunno what kind of hoops an international cooperation has to jump through with Paypal, but I was in charge of setting it up for a local company that went to homes and did on site services around the house like handyman work and such. It was awesome until the first charge back, then they hit us with 7-14 day waits on all payments because "we weren't able to provide proof that the customer had received the charged services." Took upwards of 3 months of solid usage after that with no complaints or charge backs before we were able to get back to instant deposit. Can imagine they had to take some time to work out terms and such to avoid situations like that. 3ish months for a no name company I get, but for a larger, international, traded company, it seems a bit extreme.
Not related to SE but in regards to the example.
A signed off completion of work added to the bottom of work orders should be sufficient. Just one line and a spot for a signature.
Paypal in general can be a big itch both on payment and being paid. They tend to work on a authorized debit first basis, which requires by laws/regs much more hoops than credit transactions.