Table 4D1A

Table 4D1A has cables that when reference method F is used starting at 25mm^2, I cannot find a suitable explanation as to why 25mm^2 single insulated cables are okay to use at this CSA and not any less.

If I used 25mm^2 cable from this table the insulation is still the same as a smaller cable from the same table.

is there any justification that when the cable gets to 25mm^2 it somehow becomes acceptable to use?