should i seal before painting exterior rendered house?

Hi all, I'm currently working my way around the exterior of my house using dulux weather shield. I totally underestimated the amount of paint that I required. The manufacturers guides are well out. I. Bought 9 x 5l tins and am not even half way around.

The walls are a smooth render (on 3 plus year) that has be jetted.

I wondered if I should be adding any pva or sealing first to get more out of the paint?

Cheers, Devs.

9 tins used, you must have one very big house, should be getting 16m² per litre so that's 80m² per tin and 720m² with 9 tins even if you half that that is still a large area
You can thin it one part water to ten parts paint and see if that improves the flow, I'm guessing it's been previously painted.

Don't use PVA anywhere near it. If the render is raw, a thinned down mist coat of whatever your using is suffice. If its already painted, as Morpheus says, thin your paint a bit to aid flow and coverage.