Partial group of text effects always renders as words

The partial group parameter for text effects seems not to be working for me - no matter what I change the setting to (letters, lines) the effect always renders as words.

For example - I am trying to use default settings for 3d CamDepth - Gentle_Falling preset.

All I am changing is the partial group parameter to letters, but the effect always comes in as words.

Never mind - I see one has to edit the other parameters as well, such as partialPercent...