getPeople().increment() has a glitch when manually changed

[tomasbaran]

1. Let's suppose I have a credits property at value: 80
2. I need to change the value manually in the user profile from the dashboard to 100
3. getPeople().increment() stops working

I guess 3. stops working because it is NOT treating the manual change of 100 as double but as String "100" rather — only my guess.