Quite common.

The mean of a dozen in 2400 spins: 2400 * 12/37 = 778,378

STD for a dozen in 2400 spins: (2400 * 12/37 * 25/37)^1/2 = 22,933

So, 1STD: 22,933

2STD: 45,866

3STD: 68,799

4STD: 91,732

3 and 4 STD are quite normal, so assuming you have 3STD you can have 778,378 + 68,799 = 847,177 hits.

Hitting 847 times you have a profit of 1694 and you loose other 1553 bets. 1694-1553 = 141 units (between 3STD and 4STD, but closer to 3).

So yes, you had luck selecting that dozen but the numbers spun are in a normal range.