Call me cynical but as one who has worked for the CAA and nats for the past thirty years just bear with me. There may be other factors that are not obvious.
1) There is a way to break bad news and that is to give VERY bad news first and then when the truth is known it seems like good news.
2) There are a lot of very senior people who if they stay after 8th April 2010 will be obliged to stay until the age of 55, however if you suggest that they may be problems with the pension fund then rather than take the risk they will leave voluntarily and that would save nats enhanced retirement and salary costs.
3) This is no criticism of the respective union reps, but if the unions have no influence over Mr Barron or the management then let them be honest and say so and then we can make up our own minds as to where our personal interests lay and then we can plan accordingly.
In conclusion these MAY be factors in the managements plans particularly No2