Yes I can explain.
Your version of the "Boeing Manual" is an airline customised version so someone other than Boeing has added an extra dot point. The only true document is the one that is on My Boeing Fleet, and I don't have access to that at home.
There are only five dot points in my Boeing Manual.
ALPHA floor is a term from Airbus (from their aircraft) which is the ultimate stall protection. I do not know enough about the Airbus to explain all the ins and out of its workings.
For the B737 the auto-throttle will increase thrust to maintain its minimum speed (the books say approx 1.3 v/s) however what the book does not say is that if the MCP altitude is above current altitude that is true however if below the current altitude then the thrust will close and the elevator will pitch down to minimum speed. Min Speed reversion is an MCP SPD mode.
From My company Boeing manual.
Autothrottle Engagement
Moving the A/T arm switch to ARM arms the A/T for engagement in the N1, MCP SPD or FMC SPD mode. The A/T arm switch is magnetically held at ARM and releases to OFF when the A/T becomes disengaged.
A general summary of A/T mode engagement is as follows:
• A/T SPD or N1 modes automatically engage when AFDS command pitch
modes become engaged
• Engaging LVL CHG or VNAV climb modes automatically engages the
A/T N1 mode
• Engaging LVL CHG or VNAV descent modes automatically engages the
A/T in RETARD and then ARM when thrust is at idle
• If not in a VNAV mode, engagement of ALT ACQ or ALT HOLD
automatically engages the A/T in the MCP SPD mode; otherwise the A/T
remains in FMC SPD.
• Engagement of G/S capture automatically engages the A/T in the MCP
SPD mode.
The AFDS and A/T do not control to a speed which is less than minimum speed for the current flap configuration. This speed is approximately 1.3 Vs. Minimum speed, FMC speed, or selected speed, whichever is higher, becomes the AFS commanded speed. If actual speed becomes equal to or slightly less than the minimum speed, the underspeed limiting symbol appears in the MCP IAS/Mach display, and if operating in the V/S mode, the AFDS reverts to LVL CHG. The AFDS will also revert to LVL CHG from VNAV PTH, except when capturing or flying a level segment.
The AFDS commands a speed 5 knots greater than minimum speed. Selecting a speed 15 knots greater than minimum speed reactivates normal MCP speed selection control. The AFDS commands nose down pitch to increase airspeed if the thrust levers are not advanced. When actual speed becomes 15 knots greater than minimum speed, the underspeed limiting symbol disappears.
The A/P disengages, and the F/D command bars retract when in a LVL CHG climb with a command speed equal to minimum speed and a minimum rate of climb cannot be maintained without decelerating.
Minimum speed reversion is not available when the A/T is OFF and the AFDS is in ALT HOLD, ALT ACQ, or after G/S capture. Minimum speed reversion is also not available when in VNAV PTH and capturing or flying a level segment.