It's 10 degrees. That is the deflection one could use for a light crosswind, so it is obviously expected that spoiler upfloat will occur for stronger crosswinds. Boeing is suggesting not overdoing it
unnecessarily. It is that last word that is generating the discussion.
Out of interest, I referred to the Bible, DP Davies' 'Handline the Biggies':
So take care when operating in crosswinds. On take-off, set in a little into-wind aileron control quite early in the take-off run whether or not you feel it is necessary, this will stop the down wind roll which will otherwise occur just before lift-off.
According to the 747 official company manual, that was 1 division/5kts, so a 15 kt Xwind would give you quite large deflection of the wheel, which was acceptable- hard to estimate, but I would think >20 degrees. It would seem the 737 doesn't suffer the same degree of wing lift on take-off.