Sorry if I'm not explaining it properly. If I had cut the steerer tube 2 more mm. the top cap would have inserted flush with the top of the stem as is recommended. Because I left the steerer tube 2 mm. too long, when I Insert the compression plug/top cap into the steerer it doesn't flush up against the top of the stem. There is a 2 mm. gap between the top of the stem and the top cap. I already have 30 mm. of spacers under the stem which is the max recommended by the bike manufacturer. If I add the two millimeter spacer there I exceed the limit. I don't know how critical that is since I have never owned a bike with a carbon steerer prior to this build. Can one be added on top of the stem as someone else suggested ? If I do that, the the compression plug which is under the top cap will be about 4 mm. higher in the tube than where it ideally should be. Again never building a bike with a compression plug I don't know how critical that is.