how is the power per frequency related to energy of discrete wavelet coefficients

i have data whose sampling frequency is 1K. i did fft of the data to check the frequency components present. then i performed discrete wavelet transformation and plotted the result as colored image. i found out that the signal had max power at 6.67 Hz but in my dwt plot,the deep red occurs in the frequency range 7-15 hz. would anyone explain me what is the reason?

any help or suggestion is appreciated