Does this sound natural?

I'm working 6 hours a day and 5 days a week.
Most companies pay extra money for overwork, but in my company, there's a little strange payment rule.
For example, if I overwork 1 hour, I can go home 1 hour earlier or go to work 1 hour later someday.
And if the total time of overwork for 1 month is 6 hours, I can take 1 day off.
I liked this system, because the harder I work, the more days off I can take, although the salary is the same.
In addition, I have 20 paid leaves per year, so recently I'm working only three quarters of usual office days and I liked it.
However, recently I noticed it was a vicious circle, because no matter how many days off I take, the amount of the work per month is the same.
So the more days off I take, the busier I get and the more I have to overwork, which means I need to take more days off.
Recently I'm getting tired, even though I have a lot days off.
It may sound funny, but now I'm wondering if I should talk to the manager about it.