Units are a normalized stake used for record-keeping. They are not a statement about money wagered.
ROI = net units won or lost ÷ units risked.
Why units or ROI may say "Unavailable"
Units and ROI need the price (odds) of every graded pick. Many picks are posted without a price. When any graded pick in your selected range has no posted price, PickBot shows units and ROI as Unavailable rather than estimate them.
Your record and win rate are still shown.