Indicator Buffer does Not Allocate Memory for All Indicators?

 
Greetings, I'm trying to create an envelop around an SMA, so altogether I have 3 indicators i.e. SMA itself, the upper band and the lower band. In my code, indicator buffers allocates memory for maximum allowable 8 indicators. However, only 2 first indicators (out of 3) show up on the chart. The values for all 3 indicators get properly calculated. Could please someone have a fresh look at my code and hopefully identify what's causing the issue? Thank you in advance.
Files:
envelop.mq4  2 kb
 
You assign only 3 buffers. 8 buffers are allocated but only 3 of them are accessed.

Declare 5 additional buffers and assign it with SetIndexBuffer function. For more details read 'Features of Custom Indicators Creation'
Reason: