Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 28°C. We apply continuously 71°C heat to the field 1x7
What is the temperature (rounded to whole numbers) in the field 9x8 after 90 iterations according to the Gauss-Seidel iteration

Field in the beginning

28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828
28282828282828282828

Field after 4 iterations (rounded after 4th iteration)

47899109863
711141516171615116
814182021212119147
916202224242421168
1019232526262523179
1629313029282623189
2755453631282723179
44124624031272421158
2753413124211915115
12212016131110863

Temperature in field 9x8 after 90 iterations: