The times are right, but it's a common misconception that they are wrong and here's why. Take a VBase with three hangers. Each hanger will be down for 15 minutes. Only one hanger has to be up for vehicles to be enabled.
You take down the first hanger.
Five minutes later, you take down the second hanger.
Five minutes later, you take down the third hanger.
Five minutes later, the first hanger pops back up (since 15 minutes has passed).
You think "
?! Hangers were only down for five minutes?!"
Ack is even more misleading because it is very easy to take one down by accident. Let's say some Vulcher decides to take out the radar at a vbase and also blows up the ack next to the radar in the process. Half an hour later, a huge NOE group sweeps in, deacking the base and taking down the vehicle hangers. Fifteen minutes later, in comes the goon... out go the troops.. and
THEY'RE ALL DEAD! What the HECK?!?! Ack was only down for fifteen minutes!!! The chart MUST be wrong! But it's not...
And the whole time the Bish are watching this unfold from the tower going