I think of it as zero syns but not free
if you were to eat a neat tbsp then it would cost 1/2 syn (bleurgh!)
but usually I add 1 tbsp to a dish which feeds 3-4, so I'm having a 1/3rd or a 1/4 of 1/2 a syn...which I'm willing to see as negligible, and so zero if not actually free IYKWIM
if however you guzzle a whole tube to yourself then you should syn it!