Today (06/12/2017) Bing rolled out the announced change to Device Targeting, allowing for broader bid modifiers and complete opt-out for tablet computers. As well, for the first time, Bing does now offer the option to completely opt out from displaying ads on desktop computers.  For the rest of the bid adjustment range, the new scale is set between  -100% to + 900%.

According to Bing the rollout is globally and will be reflected in Bing Ads Editor, Bing Ads Web Interface as well as Bing Ads.