The same scare tactic was used to coax us to sign the COS94 (you will never get a basing and you will never get another payscale increase). The 5% who remained on the old pre-COS94 ended up having a fantastic roster (their overtime rates were punitive compared to the new rates) and also remuneration and leave for the following 5 years. So good was the old COS, that the Management eventually forced the pre-COS94 guys onto the COS99 with a sign or you are sacked letter from the DFO, which was followed up with a similar threatening letter from the CEO (the same letter we all got from the suckholes of the time).
Any NEW COS is cunningly designed to benefit the Management and NOT the aircrew. If you think otherwise, you have been had...