Do power chains lose their strength?

A gap formed between my two front teeth during my first few months with my brace on. it’s only small, maybe just over 1mm. I had a power chain put on about 10 days ago and over the first few days it seemed to close the majority of the gap. I’m now left with maybe 0.5mm gap but progress seems to have drawn to a halt. I have 3 weeks until my next appointment. Will the gap continue closing in this time or do the chains lose their effectiveness early on?