In NPPL Microlight world, there is a requirement for at least five hours navigation training of which at least three hours must be solo.
I have had students with 110 mins dual and 190 solo, and that has been satis with BMAA and their CAA auditors.
So minimum 4 hours means just that, and so could be 10 hours solo supervised. If they wanted different, then they should have written minimum 6 hours dual and 4 hours solo.
But one can obviously stretch it to 4hr 10 min solo and 5 hr 50min dual - and then just keep stretching.
It is not what is meant, it is what is written.