PIF is more important than PIE.
PIE are Parity Inner Errors (correctable and uncorrectable). PIF are the PI Errors that could not be corrected by the PI Error Correcting Code. The PIF must then be corrected by the Parity Outer ECC, or if they fail that you have a POF (Parity Outer Failure), which means that the drive will have to try to re-read that sector or produce a real error.
The PIF maximum should also be taken into account, not just the sum.
None of the PIE and PIF numbers you quote are very high, so you could burn your next couple of DVDs at 2x and 4x and scan those also.
If you get a consistent result of one speed giving lower PIF-sum and the same or lower PIF-max, then you can use that speed in future burns.