Doubt about late payment of service tax (Section 75)

I am not having any recent Notification/clarification to support my post but a Notification was issued by Commissioner of Central Excise, Mumbai wherein Trade Notice No.7/97 dated 04.07.1997 was produced. Please refer to Para No. 4 (III) of the Trade Notice, which is as follows:

"III) Interest on Delayed Payment of Service Tax

 If any assessee fails to pay or credit the Service Tax or any part thereof in time, he shall pay simple interest @ 1.5% for every month or part of a month by which such payment/crediting of the tax or any part thereof is delayed."

https://www.servicetax.gov.in/trade7-97.htm

This being an old notice may be outdated, but as per my knowledge, so far no clarification has been issued by the Board on claculation of interest on delayed payment of Service Tax.

As most of the post support calculation on number of days basis, I doubt that my concepts are not up to date as far as calculation of interest is concerned. So I request that if anyone is having information about clarification issued by the Board for claculation of interest, especially those who support calculation on number of days basis, please share the clarification here to support your view and help me update my knowledge on this subject.

Thanks in advance.

Dear All,

can any one clear my doubt about ,

     is interest and penalty different need to be paid ?

Inerest is 18% that i can understand , and  should i calculate penalty of late returns of service tax separate  ??

please can any one reply me ??