Why dpss of mtspec are different from dpss of MATLAB?

[CovMat]

Dear Krischer,

This figure shows the tapers of dpss given by tapers, lamb, theta = dpss( 5001, 4, 7 )

However, if I use following MATLAB code to plot the tapers of dpss, the results are different:

[E,V] = dpss(5001,4,7);
E = E';
plot(E(1,:),'.-')
hold on;
plot(E(2,:),'.-')
plot(E(3,:),'.-')
plot(E(4,:),'.-')
plot(E(5,:),'.-')
plot(E(6,:),'.-')
plot(E(7,:),'.-')

I am confused why they are different. Looking forward to your reply. Thanks.