Dormition II

On Monday August 1, we entered the Transfiguration/Dormition Fast, which continues through 8/14. (It's usually just called the Dormition Fast.) And it occurred to me that Orthodox commemorate Mary's falling asleep on the 15th, but the West, her Assumption, which we say took place within three days of her burial. That is, the Assumption may have taken place right after she was buried; all we know for sure is that her tomb was empty on the third day when St. Thomas, in God's Providence, arrived from India and found it so.

Considering that the West is agnostic concerning her death, who is more credible?