Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 7°C. We apply continuously 168°C heat to the field 4x8
What is the temperature (rounded to whole numbers) in the field 0x6 after 139 iterations according to the Gauss-Seidel iteration

Field in the beginning

7777777777
7777777777
7777777777
7777777777
7777777777
7777777777
7777777777
7777777777
7777777777
7777777777

Field after 4 iterations (rounded after 4th iteration)

1222222221
2334444431
2345555542
2456666542
2456777642
2459131311853
249223630201374
262154100643519104
2933962631054622104
2721519156291473

Temperature in field 0x6 after 139 iterations: