I started this thread based on the information provided on the public face of Gain i.e. their website Gainbitcoin.com.
This info and this website have proved to be misleading, downright false and more typical in mathematics of a standard R*ssian HYIP than a legitimate business.
On the website, a starter pack Basic Plan investment is 1BTC.


No.
My personal view of mining bitcoin is that it's marginally profitable at best and then only for the largest operations directly. With cloudmining you then add in a layer of obfuscation and (deliberately) misleading projected returns and often a highly expensive MLM sales structure: it becomes untenable from a risk/reward pov.
Having said that, and emphasising that I don't recommend investing in this area, have a look at Eric Mu's attempt at a transparent operation here.

In the bigger picture, the concept of "growing" your BTC is being pushed hard by people whose interests are primarily to get their hands on your money.
The idea that Bitcoin is a self contained environment in which the man in the street can profitably operate is a false one in my opinion.
If you are in the Bitcoin space then it's a reasonable assumption that you are bullish about its future and therefore its price.
The simple approach for profit is to buy and hold bitcoin, increasing your holding by investing surplus fiat that you generate in real life by whatever your job is.
At the moment it is an interesting investment opportunity to be indulged in with the greatest care, with a potential to grow exponentially as problems are solved and longer term credibility is established.
This is why I spend some time "scam busting". I see the potential for good financially and socially in Bitcoin but every time thieves and liars succeed, its credibility and progress are compromised.
Good luck.