Would it be correct to change this...
"He agreed to those changes, but insisted that if the team do not reach the objective by the deadline, the company must commit to implement all the modifications"
...into this?
"He agreed to those changes, but insisted that if the team did not reach the objective by the deadline, the company had to commit to implement all the modifications"
(Additional info: the deadline specified was a year after the discussion, and three years before the document)