Calculating Attack Speed with Burrows

Level 12
May 9, 2009
I was wondering how does the burrow ability work on the attack speed of the unit. The original attack speed evidently increases but does anyone know the connection between max cargo hold, current cargo hold, and attack speed? I am using a cargo hold that fits only 1 unit and the attack speed seems bonus seems to me seems like it's a percentage thing as units with higher attack cooldowns get a bigger attack speed bonus. This makes it very hard to accurately predict the final attack speed of the building.