It seems that the maximum amount of fuel and supplies that can be stocked in a base depend on its size.
For example, in a port size 1 (or 0, I can't remember), I couldn't delivery more than 100 fuel, the excess is lost.
Does anibody know the maximum of goods that can be put in the different size bases?

tanjman is right. In fact, my TF is drinking a part of the fuel as soon as it is delivery. Thanks.