You're asking a lot of an XML.
Something to try:
select all clips and copy them. create a new timeline with the same sequence properties. make sure CTI is at beginning and paste.
in this new sequence, select a clip that has not had speed changed (100%). right click on it and select copy properties. select all clips and paste properties.
BE ADVISED THAT THIS WILL CHANGE ALL CLIPS TO THE SAME PROPERTIES AS THE ORIGINAL.
this may reset all your In & Out points to their proper duration. if so, you can then adjust the timing of the requisite clips as necessary.
For best results using XML files, there should be NO: effects, dissolves, "black slugs," audio mixing or anything other than a plain vanilla straight cut.