Mobile Device Detecting UserAgent Matching order

I am working on CQ5 mobile template device detection, here are some of the constrains/requirements:

• We dont have latest version of WURFL DB and neither we can update to latest.
• Only have two device groups Mobile (smart phones, Tablets) and Desktop

I basically want to verify the order in which device detection happens, as per my understanding it is following order:

1. Look into WURFL database for device
2. If not found in WURFL database then look for RegEx (/libs/wcm/mobile/wurfl/regex) to match to WURFL device mapping
3. If not found (in #2) then goto nomatch case
4. If found (in #2) then match UserAgent (which can be a regex) with defined deviced for the page heirarchy

Please enlight if this order seems incorrect or incomplete.

Given that this order is correct than if there a way to have it do the UserAgent check in #4 first and dont bother checking the whole WURFL database?

Thanks in advance!