If you are using software packages though, you might consider applying pre-requisites that lock them to a specific OS type. I haven't tested this myself, but that might allow you to put OS/Bit-Level specific packages together in a single template and only have the correct one apply. Probably need to allow continue on failure though.
Just something to try, no guarantees.
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'Continue on failure' i found that to be helpful especially since it will continue at Step 4 (for example) and not start all over again. But it looks like it's a bit hard to do an OS check with LANDesk in provisioning and branch off from there. In my script i can handdle this much neater then LANDesk.
One elegant solution that i found in LANDesk is nested provisioning templates.
I can have my OS-Check script as a separate template and then import this template into another template.