People spending money on a Seneca and not bothering to fit a fuel flow are stupid!
Rather a harsh statement - if it was such an obvious requirement why was it not factory-fitted?
Procuring things like a JPI in Africa (and I include RSA) is not as simple as phoning a local supplier. Factor in the exchange rate, importation duty and the local aviation authority and it is quite easy to see why it was not a "must-have".
I have flown across sub-Saharan Africa and up and down it. I've never run out of fuel but I can forsee situations that most could never perceive.