Technically, Scroll is a "Layout" for text, not a behavior.
Stop applies only to behaviors. It's actually rather terrible to use because once the Stop Ends, animation is resumed at the point the object would have been if the Stop had never been applied — i.e., there's a "jump" in the animation.
My recommendation would be to use 2 Ramp Behaviors — one for the animation up to the stop and one to continue after a pause.
Ramp Behavior Start and End Values are "additive" to the current parameter value so you can set the position of the text anywhere you like. Since you're animating the text from the bottom of the screen upwards, you would apply the 2 Ramps to the Text > Position > Y parameter. The first Ramp will have a negative Start Value (as much as is needed) and the second Ramp will have a positive End Value.
Set the End Offset of the first ramp to be a little before the middle of the project (if a 300 frame project, then about 180 - Ramp End is counted from the end of the project to the beginning) and the Start Offset of the second Ramp to a little after the middle of the project (usually the same value you used for the End Value of the first Ramp). [You could just set the lengths of the Ramps to as long as they are needed and ignore the Start/End Offsets altogether...]
Play with the Curvatures to get an "easing" effect for the animation.
If you are making this effect for Final Cut, realize that however long you make the title in Final Cut's storyline will make the Ramp behaviors "speed" adjusted accordingly — that is, if you stretch out the title in Final Cut it will still be as if there are only the same number of "frames" as your Motion project's length, and the animation will slow down. There are two options: one is to use Build In/Build Out (Mandatory or Optional) markers and the other is to "embrace" the retiming in Final Cut. This can be accomplished by applying the Start/End Offsets to Rig Sliders and using the "timing" created by these parameters as Percent of Length of Clip.
Let us know how you want to progress from here...
