Does the effect of the Boots of Speed magic item last for 9 rounds, or 11?

Question

On page 606 of the Pathfinder 2e Core Rulebook, the description of the Boots of Speed reads (emphasis mine):

[...] You click the heels of the boots together and gain the quickened condition for one minute. [...]

Further reading of the description of the quickened condition on page 622 states:

[...] Because quickened has its effect at the start of your turn, you don't immediately gain actions if you become quickened during your turn.

I understand all of this without issue. However, if the duration for the Boots of Speed is one minute (activating when the action to do so [clicking of the heels] takes place), then the duration would expire with only 9 rounds of actually being quickened.

Does the duration of the effect of the boots of speed delay or get stretched to allow for the 10 rounds that go by in 1 minute? Or does the player lose 1 round of being quickened?

Answer 1

9 rounds

Unless your group doesn't like the ruling, unfortunately, you "lose" one round of Quickened effects that you activate. Digging into Effects' Duration

For an effect that lasts a number of rounds, the remaining duration decreases by 1 at the start of each turn of the creature that created the effect.

and Step 1: Start your Turn

• If you created an effect lasting for a certain number of rounds, reduce the number of rounds remaining by 1.
  [...]
  The last step of starting your turn is always the same.
• Regain your 3 actions and 1 reaction.

makes it pretty clear that you must reduce the duration of the Boots of Speed effect by one before you regain your Actions/Quickened Action.