5F6B,
I suppose it's an extension of the "if they all take it we can't afford it" argument; in expanding the bracket this year, there are some in the group offered without Qs or imminent promotion prospects.
What would happen if a majority accepted? Could the wider Manning plot then cope with a mass of PAS on the sqns? Admitedly, this is highly unlikely to be a factor with the current offer but I suspect that Manning are being very careful in making promises.
Either way, it's not exactly a savoury offer to those in that predicament.
Also, isn't there a QR about getting preference of last tour (ops-permitting)?