Timing Tool:

Change the time spacing between previous & next keyframes of currentTime.

How to Use:

1.Open Keyframe tools, click on Timing tool title if it's folded.

2.Select objects you want to change their time spacing, put current frame in that time area.

3.Drag the slider to set the target spacing frames.

4.Press Change button to change absolute time spacing frames.

5.Press "+>" or "<-" button to relatively add/subtract time spacing frames.

Some UI elements:        

Set time of 2Keys: Change the absolute spacing frames between the previous & next keyframes.

The digital button of the first row: Quickly add / subtract certain value to the targetFrames.

GET button: Get current actual spacing frames into the field.

Change Button: Change the spacing frames between the previous & next keyframes.        

-/+ time of 2Keys: Add / subtract frame count between the previous & next keyframes relatively.

Drag the slider to set the relative value.

+> / <- button: Change the spacing frames between the previous & next keyframes by the increment/ decrement.