Take those cautions with a grain of salt. Yes many products will have problems with expansion in larger areas but the amount of surface we are dealing with in a trailer the expansion will be lost in the noise.
I have had my Armstrong floating floor in for 10 years and have never seen any evidence of movement.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles