The BAQ performance inconsistencies with adding or not adding the “Company = CurrComp” criteria, have been resolved with work done in 10.2.700. Prior to that work, the BAQ engine would automatically use a Temp Table it populated with valid Company values for the query and the TT would be “joined” to the Company column. Depending on what other criteria was in play, that join could result in sub-optimal performance.
The BAQ has to account for a number of different scenarios including Cross Company BAQs and BAQs against tables where the Company column can be empty (generally Ice Tables where an empty Company value is an indication the record is available to all companies) so syntax and constructs that may at first blush appear simple, are not necessarily so…