Different phase response plots using MATLAB's $\tt freqz$ and $\tt fvtool$?
Citing the help output of freqz:

[H,W] = freqz(B,A,N) returns the N-point complex frequency response
vector H and the N-point frequency vector W in radians/sample of
the filter.


So, your output is not amplitude and phase, but (complex) transfer function and frequency. Hence, to plot the phase using freqz you need to use

plt(w, angle(h));