In economics this effect is called a 100% marginal tax. If you earn 1 SP you lose 1 delegated SP (out of the 15 you get at start). Just like in a welfare program. You lose your benefits when you get any income. In the ratio 1:1

This is one of the main problems with helping the poor using welfare programs. It gives the poor no incentive to work. Because they don’t increase their income when losing benefits in a 1:1 ratio to their increased income from work.

There are many proposed solutions for this problem. A popular solution is basic income. You get to keep the welfare in addition to whatever you earn. This way it doesn’t kill the incentive to work. You always get better off by increasing your income.