I think Eothese's question is related to the first number in the line which is the number of units avalable when the building is constructed. Technically he should get that one unit but with the 0.99 pool number can only retrain it (no further units available). Unless the 'below one' pool number somehow overules that.
Edit: just tested - the pool number overrules the 'initial unit number' if the pool number is below one. The second recruit line with a 'full' pool number only makes sense if it is linked to a hidden resource, like it is done in the campaigns. Example: recruiting units only in Europe but retraining them anywhere will have two recruit lines per building level, one with a regular pool entry and the hidden resource requirement, and a second line with the .99 pool number.
Edit2: or you put the .99 pool number in the core building (allowing units to be retrained without their building) and the regular pool number into a individual building.