Wavelet transform wavdec returns matrix of the wrong size
this is due to the fact that the default boundary handling is symmetric extension, which requires several coefficients more in order to achieve the perfect reconstruction. Try

dwtmode('per')

to use periodization to set the representation to be non-redundant. This will however be non-redundant only for input signal lengths being integer multiples of 2^J, where J is number of wavedec levels. Otherwise, very strange padding is used in every step of the wavedec.

P.S.: Sorry for the late answer :)