My 457b has a 50% match up to the federal max of $18k, so I contribute $18k each year and they contribute another $9k.
How long have you been contributing $18k and having it matched with $9k annually in your 457b? I'd love to be wrong, but it's my understanding that with 457b's, unlike with a 403b/401k, $18k is the max for you and your employer to put in together (until you're over 50), meaning that if they match you 50% you would only put in $12k and they would put in $6k, whereas with a 401k/403b an employer can put in up to $53k yearly (or $53k minus the employee's $18k contribution).
One thing I'd look into is whether or not your job also has a 403b/401k option. At one state hospital I've considered working at, employees can have a 457b, a 403b, and either the state pension plan or the ORP (optional retirement plan), enabling someone to tax defer more than $50K per year.
This link does a fair job of discussing employer contribution limits:
https://www.ncompliance.com/employercontributions.aspx