Not sure, what you are exactly meaning with "moving up or down". This is what the Main Manual says regarding Rig Navigation Cross:
Use this to navigate through the Rigs. Left and right buttons will switch sequentially, while the up and down buttons will change in larger steps. A newly selected Rig is instantly recalled.
So if you for example sort by date, your Rig loaded has creation date June 4th, 2020, and you press the up button of the Rig Navigation Cross, it will skip other Rig created on that date and for example load a Rig created on June 5th, 2020 - the next higher creation date.. If you sort by author, the up button skips Rigs of the same author and jumps to the next author. If you want to move Rig by Rig press the right or left button of the Rig Navigation Cross instead.
And this is, what the manual says regarding the Up/Down Buttons of the Remote:
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In Browser Mode, you can step or scroll through Rigs in your browse pool according to the selected View and Sort Order criteria. The option “Group of 5/Single Rig” on page Remote Settings in System Settings determines, if the Up/Down Buttons step through the Rigs individually or by groups of five in Browser Mode.
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By default the Bank Up botton moves five Rig forward and therefor skips 4 Rigs. That's the whole idea of a bank. You have got the Rig Buttons 1-5 of the Remote to navigate within the Bank/Performance.