According to Bartenura on Mishna Sukkah 1:1, the calculation for the minimum Succah footage is the footage one man occupies (1 Ama x 1 Ama), i.g. 6 by 6 Tfachim and 1 Tefach for his table:
שהסוכה צריכה שתהא ז׳ על ז׳ כדי שתהא מחזקת ראשו ורובו ושולחנו,
ו׳ על ו׳ לראשו ורובו, וטפח על טפח לשולחנו:
But the table is not added on two adjacent walls, only one, so the final size should be 6x7 Tfachim.
What am I missing here?