Learn English – What does “gut over” mean

It's a matter of convention, and the informal convention is that "midnight on the 10th" is more commonly the night between the 10th and the 11th. But the term is awfully ambiguous, and people do use it both ways.

(When I've scheduled things with "midnight" deadlines, I always say "11:59pm on the 10th" or something like that, to avoid the ambiguity. From experience, if you don't people will ask which you mean.)

The trick to understanding this advert comes at the beginning:

Here’s introducing iDiva: Five Magazines in One

So the publisher is saying their magazine is the equivalent of five other magazines.

Also they are selling the first issue at a cut down introductory price:

At an introductory price of Rs 5 per copy

So, in their mind, the magazine is cheap even compared to a normal magazine, but because it is five magazines in one, the cheapness is exaggerated by that multiple, so this deal is five times better than any normal discount on a magazine, i.e. five times over.