Now you cookin' with gas... :)
Don't give a **** who writes what technical manual advice, if the advice turns out to conflict with reality I'm ah-feared reality trumps the tech advice. My Concorde HATES 13.2 float at 30c. And yeah the voltage is accurate. The Lifeline loves 13.45 or if you quibble, 13.42 and remember this is at 86 degrees F.
Put a 30 ampere breaker on the CheapO. Wire a mild piezo annunciator across the breaker. This will learn-you-fast to control your hotel loads within safe limits of the CheapO. Thirty amperes of hotel loading is excessive. On my floater I am putting a momentary pushbutton with a series resistor calibrated to 14.4 volts. One little push and my panel ammeter will tell me instantly if the float voltage is set too low. Float decimal amperage will tell me if float voltage is excessive. Piece of cake.