Reporting/Group Reporting

Nope, it's far more than that, I just pointed out example. Take stats of any smaller group, then compare with giveaways and you'll see that results are completely different than expected ones.

Yes, you can say that stats are working in specific way and everybody should follow that way, it's completely OK, and in this case you don't need anything else to work with. But many (if not all) groups have their own rules, such as Arise having value of 3 for non-bundled giveaways, 1 for bundled giveaways, and 0 for shared ones. If you try to adapt that logic to fixed stats scheme of SG, you'll see that it's completely broken - not only shared giveaway add to the value, but also value is completely off gift-based. So unless you want to keep track of those things yourself (which is pretty much disrespect of your own time, my group wouldn't exist without my bot), you need automated bot such as ArchiBoT which will count all of that in the way you want, and not in the way that SG does.

Because of no SG API, I'm not sure if there exists any other tool apart from mine which is capable of doing that. SGTools can track giveaway to some degree, but still lacks some things that ArchiBoT has, not to mention that it has totally different objective in mind.

Sorry, you will need to find somebody else then. For me (and many others) time is more valuable than giveaways. Not to mention that it's not only the time but also knowledge that is required to make it working.