The point is, at the moment you earn (say) £1000 a month in variable pay on SH from doing 4 DME's, 4 3-sector days, 4 2-sector days and a standover.
On a monthly rate based on a negotiation (!) around last years total pot of variable pay, you would earn £1000 a month from doing 4 DME's, 4 3-sector days, 4 2-sector days and a standover.
The only difference is one month you might do more DME's and less 2 sector days, but the next month the opposite would be true, but your pay wouldn't change.
Simples. There was a huge debate before we changed, but since we did I've not met one pilot, top of the list or bottom of the pile, who would go back to the old system. That tells its own tale.