No, you likely saw 220 reserve minutes. Reserve minutes is how many minutes it can sustain a specified current (25 amps is standard) without dropping below a nominal voltage (10.5v is standard). A reserve minute is about 0.42 amp-hr.
The biggest deep cycles you'll find in normal sizes are around 100 amp hrs. Starting batteries are rarely rated for capacity. They are physically smaller and designed for cold cranking amps rather than capacity. The sizes vary a lot too.
A starting battery cannot sustain deep discharges without strongly decreasing the battery's life, and it gets worse if the battery is left in a partially discharged state for long periods. Exactly how much is how damaging is not well specified. I'd say 20% is safe enough if you recharge it soon.
A partially discharged battery may be unable to start a vehicle, especially in colder temperatures.
If you ask me, if it's a starting battery of unknown specs in good condition at 70F I would say 20 amp-hrs should be an absolute max to discharge it.