[34S & 31S] Unique display mode: significant figures

[mendesp]

I'm probably missing something here, but I can't figure out why I should set SIG 4 to get a 5 significant figures, like in 3.1415, instead of defining a SIG 5 format. It seems to me much easier to ask for a given number of sig figs using SIG display mode. Any explanation would be appreciated.

Regards,

Patrick