George P.
As I had earlier on mentioned, the GROOVES/LIVE DRUMS are what cause this apparent 'delay' at the start of Arranger parts after a fill/when you change from Arranger to Arranger. In many cases unfortunately (esp in the SD1 where a lot more GROOVES/SAMPLE LOOPS were incoorporated than in the X-series giving it that more true-to-life feeling), mutting/deleting the GROOVE/DRUM2 eliminates the entire drums of the style since 90% of the drum track is GROOVES rather than Keyboard drums (DRUM1). For the X1, mutting/deleting GROOVES may not have too much of an impact (except eg LATIN styles) and the intergrity of the style could still be maintained.
Probably a faster processor in a feature board might truely resolve this.