Hard to understand your post, but it appears that your high gear limit screw needs adjusting; if the indexing is smooth on all but the outermost cog (when all tension is off the cable), the only adjustment affecting the shift is the limit screw. If it is sluggish in this shift to the smallest cog in your rear cassette, the 'h' limit screw is likely too tight, and would need to be backed off and turned counter clockwise.