Back-pay deductions, it don't work out

My CSX pay-stubs revealed the following, and I would dare to say your's most likely is the same.

$1662.50 was what the carrier said we owed, but my checks say the got too much, $1876.35 as of 11/23/07 that's $213.85 too much

12/30-1/12 137.95

1/13-1/26 137.95

1/27-2/09 137.95
_____________________

$451.80

2/10-2/23 000.00

2/24-3/09 137.95

3/10-3/23 000.00

3/24-4/06 137.95

4/07-4/20 000.00

4/21-5/04 137.95
___________________

$451.80 X 2= $903.60

5/05-5/18 000.00

5/19-6/01 000.00

6/02-6/15 137.95

6/16-6/29 000.00

6/30-7/13 147.73

7/14-7/27 000.00

7/28-8/10 147.73

8/11-8/24 000.00

8/25-9/07 147.73
__________________

$581.14+$903.60=$1484.74

9/08-9/21 000.00

9/22-10/5 166.25

$166.25+$1484.74=$1650.99

+ $225.36
________

$1876.35 as of the 11/23/07 pay-check

Yet, the pay-stub states $1662.50 as per the11/23/07 pay-stub

A difference of $213.85

1$225.35

-47.60

$177.75

2/2-12/15 $123.28

1216-12/29 $000.00 Total for 2006 is 2444.80

11/3-11/16 $166.25 pay-stub shows a Total of $1828.75