I just had a look at the "Bookmaking"-Tool and the "Margin Maker":
Why can I use the "Margin Maker"-function allways on only one selection in a market???

It doesn't make any sense to me, because if you would do bookmaking you normaly lay all selections with a margin of x-%. So for example if you want to do a 110% book on the current odds in a 2 selections market you would do a 5% margin on each selection and not 10% on one and 0% on the other. Or am I wrong on that?
If it's not working within that tool, has anybody done a workaround in Excel?
Thanks
Georg