When you exec your SP use [WITH RECOMPILE] option - it forces a new plan to compiled. Old plans remains in cache and if some indexes etc changes or...

I used to have nearly similar problem. My friend coded some VBS and it worked:

While your spreadsheet is under update, it has a "deny flag" raised, VBS study if flag...

Create schema for your teset user:

CREATE SCHEMA [TESTUSER] AUTHORIZATION [TESTUSER]

and then your table in that schema:

CREATE TABLE testuser.test(name varchar(3))