xBilling - Query on Service Plan / settings

[absolutemusik]

Hi all,

I am a newbie on Sentora + xBilling.  I am running it well but I have a number of questions when trying to use.

I. Service Plan
Is it possible to have different pricing like BASIC / Advanced / professional?

Service Plans are directly linked with time and fixed price.  Is it possible to have different pricing like:
1. Basic plan as US$12 / 12 months
2. Advanced plan as US$36 / 12 months
3. Professional plan as US$50 / 12 months

II. Settings
There are some terms could not be easily understood during settings.

1. at payment method, there is IPN_URL (notify URL) for payal.  i am not sure whether the exactly meaning (likely the URL to exchange message with Paypal).  There is a form example in the same page.  What should I put in this box?

2. xBilling Frontend
For the xBilling Frontend, I would like to put /var/sentora/hostdata/zadmin/public_html/billing .
I try to type testhost.domain.net/billing/
However, it shows me 404 - file not found.

Also, I am not sure where I should put these frontend files for installation.

Thanks in advance

Willie