Are your flat lights a fairly decent exposure length? And, are you moving the EL sheet around between exposures? Are you taking flat darks? Are you taking a sufficiently large number of them to give you an SNR of between 4-5?
I took 40, 20 then rotated the EL panel 90 degrees and took 20 more, under Maxim the info window showed average 10000 aud, exposure length per flat was only .06 seconds