Carbon: floatDiffInMonths not working correctly

Hello,

I encountered an issue with the following code:

echo Carbon::parse('2000-01-15 00:00')->floatDiffInMonths('2000-02-20 00:00');

Carbon version: master of github PHP version: 7.1.3

I expected to get:

any value more than 1

But I actually get:

0.82758620689655

I tried with other dates as well and it seems to have issue. Like:

echo Carbon::parse('2018-12-16 00:00')->floatDiffInMonths('2019-12-15 00:00');

Above code must output a floating value nearing to 12 but instead output shows 10.048387096774

Thanks!