Gold Cross on top of Pesi

[Naga Sasra]

Dear Forum Members,
Over the years I have run into the Pesi top of several Keris have a cross in it, the cross is most of the time filled with gold, or as in one instance no gold just the cross.
This has puzzled me as it could be perhaps a makers mark, it could signify PB X and properly a lot of other meanings, that I would like to ask the forum to help me to identify.
I thank you in advance.