A check sends one GraphQL request from your browser straight to Twitch's endpoint at gql.twitch.tv. It does not go through vodfetch's media proxy, which exists only to satisfy the browser's CORS rules while video segments are being downloaded. That single request asks for eight fields on the channel: the internal id and login, the display name, the creation date, a small profile image, the Partner and Affiliate flags, the follower total, and the stream object — which comes back empty unless the channel is broadcasting at that second, and otherwise carries the current viewer count. Everything in the result panel is read from that one response.
Two sites can print different totals for the same channel on the same afternoon without either being wrong. An abbreviated figure such as 3.1M carries a single decimal place in millions, so by construction it cannot separate two totals that are less than 100,000 apart. Any tracker is showing the value its own last crawl recorded, which can be hours old. This page prints the integer Twitch returns at the instant you click, with no rounding step and only your locale's thousands separators applied, so two checks a few minutes apart on a busy channel can legitimately differ. The Check again button re-runs the whole request rather than redisplaying the previous answer. A follow can also be withdrawn, so the total moves in both directions.
Read the supporting lines precisely. Account age is floored to whole years — the elapsed time since the creation date is divided by a 365.25-day year and rounded down — so "about 4 years" can mean four years and eleven months; the exact creation date is printed beside it in your device's date format. The role badge shows at most one label: Partner if Twitch flags the channel as a Partner, otherwise Affiliate, otherwise nothing at all. The live badge and its viewer count appear only while the channel is actually broadcasting. A name Twitch does not recognise returns "No channel with this name" rather than a count of zero — a channel that genuinely exists with no followers is shown as 0.