'scholar':
The appearance of the summer solstice on the 9th of the 3rd month is irrelevant to the lunar eclipse of the 15th of the third month for it is simply one of the many astronomical observations computed or observed contained in the tablet.
Huh?
Maybe read slowly so you understand.
The... 15th... is 6 days after the... 9th.
The... solstice.. on the... 9th... is necessarily... within a day of 29 June.
6... days... after... 29 June... is... 5 July.
It is physically impossible for the eclipse in question to occur on 15 July.
(I hope that last bit wasn't too fast for you.)