hi, I am analyzing the ecg signal in matlab, i use wavelet transform and signal is decompased. I find a smooth signal. But i dont understand, value of axis is change WHY?

if flag==2 flag=3;

                        [c,l]=wavedec(nfile,8,'db8');

                        ca1=appcoef(c,l,'db8',1);
                        ca2=appcoef(c,l,'db8',2);
                        ca3=appcoef(c,l,'db8',3);
                        ca4=appcoef(c,l,'db8',4);
                           figure(2),plot(ca1,'-k'),title('Cofficients of Signal At l Level Decomposition')
                            figure(3),plot(ca2,'-k'),title('Cofficients of Signal At 2 Level Decomposition')
                             figure(4),plot(ca3,'-k'),title('Cofficients of Signal At 3 Level Decomposition')
                              figure(5),plot(ca4,'-r'),title('Cofficients of Signal At 4 Level Decomposition')
                              flag=3 ;