Whatever the accuracy of the RNP-AR, it is still a requirement to fly the part below minimum manual AND be visual with the runway(environment). If not, Go Around.
The approach is designed to be safe and get you to a position near the runway if you stay within the designed limits.
If the .3 or .15 allowable deveation does not bring you to an acceptable, but safe, position to land, then don't land.
If it looks good at MDA continue, but keep in mind that any weatherdeterioration after that also mandates a Go-Around.