Nah, it was only the waters gathered below that were called seas.You're welcome to believe what you like, but the "waters above the firmament" became Seas, if you follow what is said closely.
Because it's illogical. That's why.
Genesis 1 ESV
(7) And God made the expanse and separated the waters that were under the expanse from the waters that were above the expanse. And it was so.
(8) And God called the expanse Heaven. And there was evening and there was morning, the second day.
(9) And God said, “Let the waters under the heavens be gathered together into one place, and let the dry land appear.” And it was so.
(10) God called the dry land Earth, and the waters that were gathered together he called Seas. And God saw that it was good.