There is an issue for trial when a plaintiff claiming disability or gender discrimination claims that she can perform all required work within a shorter amount of time; absent a showing to the contrary, the task is not necessarily defined by the number of hours required.
Employer can be estopped from claiming that the amount of leave taken exceeds that protected by the Act when the employee relies to her detriment on an assertion to the contrary, presenting an issue for trial.
http://www.opn.ca6.uscourts.gov/opinions.pdf/18a0140p-06.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.