This move by the Company is the equivalent of circumventing the negotiations committee, and should not be tolerated by the Union. By letting the Company sweeten the pot after the LOA was negotiated and voted on by the pilots, sets a very dangerous precedent.
The Company threw a substandard proposal at the pilot group, in order to save money, and they miscalculated. To let them add things on top of the LOA without further negotiations, allows them to tweak the LOA up to the bare minimum that will be required to fill the slots.
Not coming back to the table with the Union, is just like calling up individual pilots and bribing them to bid the FDA. The Union needs to pull the plug on this type of tactic now.