No, there is not a linear relationship, as Jobo's research discovered. They found, however, that if you add a 5 minute presoak with tempered water, development in the Jobo should be very close to the times listed for classic small tank inversion development, that's assuming of course that the listed times are accurate.

Make sure to use a good termometer in your developer solution with your Jobo. You will probably have to set your Jobo's temp to slightly higher than your process calls for to get the right temperture in the developer, which is what is important.