Do I understand this sonar SSP stuff correctly?

[MarkShot]

I have read various documents on using the SSP information in the sub's sonar station.

I was just reading over Notfallmappe v6. It states that if two equivalent subs are listening for each other (assuming no layer) that the one located where sound travels fastest (fastest SSP) will have the best chance of detecting the other.

From my readings, I have come to understand that the opposite would be true. Due to the fact that sound waves are bent towards the slower SSP.

As I understand it:

(1) Sound waves are bent towards the slower SSP.

(2) Because of this bending behavior sound tends to travel into slower SSP water from faster SSP water and sound tends to not travel into faster SSP water from slower SSP water.

(3) Thus, if there is no layer or two subs are on the same side of a layer, then the sub in the slower SSP water has the better chance to detect the sub in the faster SSP water at some appropriate distance. (assuming equivalent subs)

(4) If there is a layer such that the water below the layer has the slowest SSP compared to water above the layer, then it is possible for a sub below the layer to hear sounds generated above the layer, but for sonar above the layer to be unable to hear sounds generated below the layer.

(5) If the layer itself should manifest the slowest SSP, then sounds which travel into the layer could be conveyed over an extended distance.

(6) If the layer itself should have the highest SSP, then this leads to a shadow zone where a hiding sub cannot be heard.

(7) Sound refracts in water in accordance to the SSP. Sound also reflects off the surface and the bottom. (This reflection is impacted by sea state and bottom type.)

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My question is do I understand this stuff right? (every time I read something new I begin to wonder)

Thanks.