Maternity Leave misunderstanding

When I converted to a FTE in October 2011, I was excited because they stated that my start date as an internal employee would be "grandfathered" back to my original start date in 04/2007. Looking at the benefits packet, I would get 26 weeks of Short Term Disability payments while I was on maternity leave (since maternity leave is paid for through Short Term Disability)plus two weeks of paid maternity leave! When looking for my coverage while I am out, we told the girl that I would be back in August. That worked perfectly for her since she is going to law school in September. My expected leave date is 02/24/2012. Everything was coming together nicely!!... Until I received the explanation of my leave in the mail: 2 weeks of paid maternity leave 5 weeks of Short Term Disability 5 weeks of UNPAID FMLA (Family Medical Leave Act) To return to work on 05/21/2012 Surely, there must be a mistake! I wrote the benefits adviser immediately and reminded her that my start date that should be in the system is 2007 (since the information must've been confused thinking I started in October, 2011, correct?). She responded back and pointed out that in the benefits packet above the information box for Short Term Disability, there was an insert that stated "if Short Term Disability is used for maternity leave, the leave is up to 6 weeks pay; C-section is up to 8 weeks. FMLA will be used for the remainder of time up to 12 weeks, unless an extension is requested". This definitely throws a curve ball. What are we going to do? I am sure that we will find a solution, but it may cost us a LOT of money! Time to go back to the drawing table and restructure the year.