Styles used in Producer

[ticktock]

Hi all.
I just started using the Producer and having 2 questions. Hope someone can help:
-   Could I have 2 styles at different time when creating a midi file in Producer?
-   I used a preset style when creating a producer file. Later after expanded it on the PSR-s970, I wanted to replace the style with a new style in the USB but the screen only showed styles in PRESET/USER. Does the new style have to be in USER?
Thank you very much.
Ted