Full disclosure: I'm coming back to VFR from 25 years of airline flying so by all means take all this with a pinch of salt.
I'm finding one of the terms used in SkyDemon to describe the various categories of fuel required for any particular flight somewhat misleading.
SkyDemon uses the term "Holding Time" fuel to describe what in IFR flying would be "Final Reserve" fuel. i.e. the quantity of fuel loaded which you hope never to have to burn. If it becomes apparent that an IFR flight will land with less than the full amount of Final Reserve fuel on board, it is expected that an emergency will be declared. IFR flight planning also requires a minimum of 30 minutes "holding fuel" to be carried, but this is fuel that you can use if required, and is in addition to Final Reserve fuel.
Part-NCO requires VFR flights to carry "minimum fuel reserves", and this is analogous to "final reserve" in IFR.
I respectfully suggest that the term "Holding Time" be changed to "Minimum Fuel Reserves" to emphasise the point that this fuel is the last drop available, and align the terminology with Part-NCO. If fuel is required for "holding", it might more appropriate to account for it separately, or even add it to the contingency fuel.
I'm new around here; not trying to change the world, just thinking out load really.