While importing CGM's the tabs/spacing are either deleted completly or changed.
Fix ?
Without getting deep into it...If you know what is being lost, you could take advantage of the fact that CGMs are text based. Do a find and replace batch to replace say a tab with a tilda. Then, either via macro in IsoDraw, or likely better yet, another batch after, convert the tilda to a tab again. Not perfect, but it'd get you what you want.