Lynda Carter on Supergirl as US President

I've always thought Lynda Carter as perfect for the Wonder Woman role - she played it perfectly. I looked forward to her playing the president on Supergirl. Usually a woman's voice deepens a bit as she gets older, but to me her voice sounded higher pitched and strained. I'm watching an old Wonder Woman show now, and her voice actually lower. Does anyone know if she maybe had a cold or something on the day of filming for Supergirl?