I suspect the XPPF can handle a 5 amp resistive load. The problem is that the devices we need to filter do not look like resistive loads.
Power (and heat) is a function of the square of the current. So if current is drawn over a relatively small conduction angle, such as near the peak of the AC waveform, the average current may be 5A, but the peak current (and resulting heating) will be much higher.
Take for example a 50% conduction angle with a 5A average load. The actual current during the portion of the cycle where power is consumed would be 10A, resulting in twice the heating relative to a resistive load with a 100% conduction angle. ((2I)^2) X 0.5 versus (I^2) x 1 So, the heating of the filter would be the same as for a 10A resistive load.
Unfortunately, most people assume a 5A current limit means the same for all loads.
Jeff