Yup, when I used to work over time, and had a really big week, the total amount on the check that went to me was quite low compared to the work. A check with 60+ hours of over time I got was quite small compared to what I was thinking it was gonna be, lol.
If the employer is paying his own jump of taxes on that it'd be quite expensive for them to, probably why they don't have me working those hours anymore.