Still having difficulty figuring maximum contribution.
Been with the same district 19 years.
9% of salary is tax deferred and sent to state teachers retirement system on my behalf.
when figuring employer contribution does that 9% get included on line 6? Is that an employer contribution for purpose of figuring the 25%
On a 50,000 salary:
50,000 minus 4,500 (9%)=includable compensation
x 20%=9100.00 plus 3,000 (over 15 years same dist).
Does this look right?

this would probably be better posted on the 403(B) board, but I will give a shot.
you did not indicate how much was previously contributed.
includable comp now includes deferrals
1. Exclusion Allowance=
20% * (50000) * 19(svc) - prior contributions=
190000 - prior contributions

2. Limit on overall contribution
50000 * 25% = 12500

3. increase in deferral for long service

19 * 5000 = 95000

95000 - prior deferrals = X

or

15000 - any extra increases previously made = Y

use the smaller of X or Y but cap at 3000. This is the amount your deferrals could be increased.