let's take it by the 'use yout logic' way...

the first would be the one with the "1" on it, which makes the "OVA series 1", right?

now we have GI and GI finals, since GI can't come after it's finals, it must mean that the GI OVA takes place before th GI finals OVA, do you need further explanantion? the fact that GI is already complete while GI finals is still in the making should have tipped you off as well...