Deep Cycle Battery Ratings

Im being offered batteries Surrete. The specs are these:

Battery Rolls S530
6V

532Ah in 100h
400Ah in 20h

I remember reading about batteries and how the important number (so to speak) was the Ah rating at or near 24h. Id like to clear that up a bit. From what I understand, the ah rating is how many amp hours a battery can produce during that alloted time, so:

During a 20h period, this battery can supply 400Ah

or

During a 100h period, this battery cans supply 400Ah

It almost seems counterintuitive because how can a battery supply MORE Ahours over a longer period of time? So i searched for the specs and sure enough, found this:

Attachment not found.

The table shows exactly that pattern where Cap/AH increases with Hr rate, so I must be reading this wrong. Then the right column reads something that makes more sense, during 100 hrs it can supply 5.32amps whereas during 1hr it can supply 144 amps. So why am I reading it wrong?

On the other hand I looked at an Optima BlueTop which has these specs:

Attachment not found.

This shows this battery's Ah rating at:

55Ah @ C/20.

And then Trojan has the following:

Attachment not found.

Where their batteries are anywhere between:

33-140 Ah at 20hr Rate.

So I imagine that the Surrette, which is a battery made specifically for RE systems, it makes sense to have 400Ah at 20Hr. I understand its quite a heavy battery and it costs around $300.

The Trojan is also known for RE systems so if it doesnt go past 140Ah at 20Hr then its because they dont consider themselves solely a RE battery maker.

Finally is that why Optima, which makes a lot of regular starting car batteries, simply has a 55Ah at 20Hr and not much more?