|start of month 1 - Current value and no loss yet
        |end of month 1|1.5%
        |end of month 2|1.5%
        |start of month 3 - this is by definition every 2 months

it is clearly stated in the exercise that calculations happen at the end of the month but the increase of percentLossByMonth is increased "every 2 months" which will mean that the first increase happens at the start of month 3.

Otherwise the first increase happens BEFORE 2 months have passed, and then every 2 months after that, which would be insane.