CDO

Hi everyone!

I'm trying to merge 4 files (each one with a season for 30 years). For that, I used:

cdo mergetime msl-JFM.nc msl-AMJ.nc msl-JAS.nc msl-OND.nc msl-year.nc

but I have an error:
cdf_put_vara_double : ncid = 327680 varid = 3 val0 = 10499.000000
Error (cdf_put_vara_double) : NetCDF: Numeric conversion not representable

I solved it with cdo -b 32 mergetime (as I've read here before), but my point is that if I try the same step with only two of them I don't have this problem (I don't know why, because these are the same files).
And I also wanted to know if I could use in that case cdo F64 ?? (sorry if this is obvious..)

Thank you in advance!

Cheers,
Noelia