In the picture, we had just finished turn 5 and the FAPLA/MPLA Alliance has a 3VP lead. Earlier in the game we gave away 1VP when we over bid on Covert Aid and we would do it again later in the game. That is 2 free VPs for the other side! That got me to thinking in the future, if my Alliance is leading in VPs, it may be best to bid zero the majority of the time and one sometimes for Covert Aid.
1. You are playing with the lead so probably have a good position and do not need aid as much as the other Alliance.
2. The other Alliance needs more help than you so may be willing to surrender VPs in the short term to build up their strength hoping to catch up with you eventually.
1. You will not get any Equipment if your Alliance always bids zero or minimal equipment if you bid one.
2. Your opponents will, depending how willing they are to give up VPs, get more Equipment than you. This may eventuallt tip the advantage to their favor.
Since the VP differential seems to be tight in the couple of games we have played so far, I think if you can get a good lead it is best not to give it away during the Covert Aid phase by your Alliance bidding zero most of the time.