More than 3 values for [SearchBy] field?

Hello,

I'm trying to search by 4 values, for example, artist, album, track count, and year, however Mp3tag's UI only ever shows a maximum of 3 input fields when running the web sources script, despite 4 (or more) values being defined, e.g.:

[SearchBy]=A||val_1||%s||B||val_2||&b=%s||C||val_3||&c=%s||D||val_4||&d=%s

Only A-C will show, with D not displaying.

Is there a current limitation of a maximum of 3 values for [SearchBy], or how do I make this work?

Thanks.

Mp3tag v3.07