"I just really struggled with the second stint, just with the high fuel load and having to carry the tyres for so long during the second stint.
"Obviously we had lost our track position as well. Technically it shouldn’t have cost us that much, but I think it did affect the outcome quite a bit.
"It’s unfortunate, I’m not too pissed off about it. Things like that happen, so it is what it is."
While disappointed not to add to its late-season haul of silverware on Sunday, team boss Tim Edwards could at least take positives from its pace beyond Mostert as a tough season nears its end.
"Obviously when you get a trophy on Saturday you want more on Sunday, so [it] was a little disappointing, but overall it was a solid weekend for us," he said.
"That’s three races in a row now with multiple cars in the [top] 10, and that’s been a challenge at times this year, so it’s a credit to the team who have worked hard and gotten us closer to the pointy end."