Likewise, the old Australian rules distinguished the two aspects in a similar manner. The certification bits (which largely piggybacked on the US (ANO 101.6) and UK (ANO 101.5) rules were then supplemented by the operational rules in ANO 20.7.1b - it was just a pity that the two had the odd discrepancy but the intention was honourable.
This led to a few problems for a while in the early stages of harmonising with the OS rules when ANO bits and pieces were tossed out in a somewhat undisciplined manner.
The use of a 15 percent fudge factor was used for considerations such as gravel runways as well
In respect of category, the usual application was that all heavy aircraft were certificated in Transport Category. For the lighties, the old and well-loved P-charts (and I had an involvement with more than a few of those) covered a range of surface conditions allowing the pilot to hazard a guess as to what might be appropriate for the particular day.
I find it more than amusing that, having thrown out the baby with the bathwater, the System in a recent crash comic is now advocating an informal return to the protocols of the P-chart algorithms... quite amazing.
Unlike the UK system at the time, I am not aware that the Australian regulator ever permitted a distinction between destination and alternate for performance matters.
The real problem is measurement of surface frictional characteristics and the general one of repeatability. Whichever way you go, be cautious when conducting contaminated surface operations if you don't have greatly excess distance and width, especially with crosswind conditions.