I think pixie Ji is absolutely right. Thats my understanding as well.
To add more to ur concerns, I don't think there is a way to upgrade EB3 to EB2 just like the way I used to think or may be U r thinking. For example, like when u file for ur H1-b, there is always you can do premium processing in the middle of the application by submitting the form and paying that extra $1000.
In case of EB3 to EB2, you have to start from beginning; this is what I have heard and has been told. You cannot send documents to USCIS and request to change them from EB3 to EB2. Becuase now everything is differnt. You are applying GC based on completely different circumstances. And also, consider Pixie's suggestions.
But, You will be still better of pulling ur EB3 application and apply EB2, which will be faster.
Few months back (3-4 months), the current for NEpal for EB3 was May 2005. I have heard maxium of 14-18 months (few 12 months) on EB2 for NEpal.
hope, more will light their ideas and views and experinece on this...