Question about Mercury's Winged Sandals (TME)

So, this came up in a game discussion: Mercury's Winged Sandals, from Transforming Mythic Europe (pg. 111). The description says that you can have up to Encumbrance/Load of 5, although it will slow you down. No problem.

However, page 107 discusses using Rego spells and requisites to carry things. It says that you'll need a requisite for the effect if your encumbrance is greater than medium (3).

So...which is it? The rules for the sandals seem fine enough, in that they're graded for how much stuff you have on you. And I suppose if you want to be technical, the guidelines on pg. 107 are for INSTANT transportation. Is this some change in the rules for flight, rather than teleportation?

(Also, how long is a turn? I thought 50 paces/turn = 17 miles an hour, on the assumption that a turn was 6 seconds. If it was 3 seconds, that "40 miles an hour" would make more sense.)

EDIT - OK, looks like a lot of the "flight" in that section of TME is a variation of levitation, rather than a straight cross-over from the Teleporatation version. As such, they are defining "move a target quickly in any direction they please" as "around 40 miles per hour". Is there any basis for that number? I don't mind, but it seems slightly arbitrary. But I guess the guidelines for teleportation are different than the flight/levitation guidelines?

40 mph is based on the speed from Wings of the Soaring Wind.

I have something a problem with Rego Corpus being able to achieve the exact same effect as Wings of the Soaring Wind (without all of the finesse, unnatural wind and requisite requirement issues), but that's more of a personal sensibility of mine than anything else. I peg "quickly" as 15 miles per hour (which for the paradigm is darn fast compared to walking or running). I've had this discussion here in the forum before. My sensibility is that while spells from different forms can mimic spells of other Forms, some things should just be done better with the right Form (tool). Corpus quickly had been undefined until TME, the authors, for whatever reason, decided that quickly, in the context of corpus, was the same as the speed granted by Wings of the Soaring Wind. So now a Rego Corpus spell makes a better flying spell than the definitive flying spell listed in the core book.

Rounds in Ars Magica are 6 seconds, therefore there are 10 of them in a minute (last paragraph of Combat Sequence section on page 172 of the core book).

Cool. Thanks for the link, Jonathan! That pretty much answered my question.