While we're beating a dead horse, here are a couple of things to add to the confusion. (And I don't want to flame contention, I just want to highlight some of the fascinating history of these patterns. The more you research them, the more contradictions come up. Just look at it as interesting)...
The 1960 Wm F. Ludwig recording of Frank Arsenault playing the 26 Standard (N.A.R.D.) American Drum Rudiments has an introduction which states, "Start each rudiment slowly. Gradually increasing speed evenly until the rudiment is closed. Then, gradually decrease speed, opening the rudiment." Whether they're diddle, flam or drag rudiments, the individual strokes are distinct and the only thing that changes is the space between them, based on the tempo. No movement is crushed and no buzzes are part of this list of 26. NARD was disbanded at the end of 1977 and lay dormant for 31 years.
In the meantime, the rudimental mantle was taken up by P.A.S., which updated the list to 40 and released a recording in 1984 with Rob Carson playing each one. The introduction states, "Each rudiment will be broken down in a traditional, rudimental contest style. The rudiment will be performed open, which is slow, to closed, which is fast, to open."
So far, this isn't a lot of conceptual difference, except when it comes to the multiple bounce roll. At this point, the instruction is, "It is recommended that the multiple bounce roll be performed in a closed manner. Start at pianissimo and crescendo to fortissimo, then diminuendo to pianissimo." This is where confusion can crop up. I look at multiple bounce as being any more than two, though an arbitrary number. But on this recording, it's clear that "closed" means buzzed. The breakdown here means quiet - loud - quiet, with a uniform buzz texture throughout. I do not detect a change in the rate that the hands alternate. And I certainly don't hear a change in roll texture; there's no modulation from say 3 strokes per hand to 4, 5 or 6. It's just one buzz or "closed movement" per hand, with each hand alternating evenly.
So this is my long winded way of saying, unless you're dealing with an old school player who knows enough to parse the difference, say "fast" for top speed.