Is it legal to change a partnership share agreement two days before a partner's last day at an LLC?

I have given my exit notice on the first week of January and my last day at the LLC is on Friday, January 31. I am a partner of four in our LLC. One of the partners called a meeting two days before my last day to discuss business percentages due to my leaving and tax reasons. He wishes to change our current, signed, and dated agreement of equal share to a new one based on how many clients we brought in to the company this past year, what unique skills have we contributed, our individual market value (?!?), etc. We will have to agree on this new agreement before my last day and the percentages will be reflected on last year's tax. None of these new guidelines were ever brought in to discussion last year. By law or good business conduct, are they allowed to do so? What can I do to protect myself from potentially getting unequal share percentage and remain in the current, dated and signed agreement?