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They are being produced as same rate, right?

It depends on what you mean by "the same rate". SBD supply is increased because of the price feed bias set by a few witnesses, so it's more SBD than usual, but also far less SBD produced than STEEM.

The inflation rate didn't change.

I mean. Theres some 2M USD worth of steem produced in a week.
75% goes do users. If I get standard payout 50% is directly in Steem and that other 50% goes to main Steemit account which sells it on internal market for SBD (?).

Ex: Right now theres a 1:1 price ratio.
So my post gets $ 10.
I get (approx.) 7.5 SBD payout - 3.75 Steem and 3.75 SBD.....
But thats not the case. Why?

First: there are 43,000 STEEM tokens printed every day, so in a week we have 301,000 STEEM tokens. At the current price, $3.6, that means $1,083,600.

Second:

If I get standard payout 50% is directly in Steem and that other 50% goes to main Steemit account which sells it on internal market for SBD (?).

I don't think I understand that. What Steemit account?

Third:

I get (approx.) 7.5 SBD payout - 3.75 Steem and 3.5 SBD.....

Almost right. You get 3.5 SBD, but you don't get 3.75 STEEM, you get $3.75 worth of STEEM. Please have a look at this reward calculator here.

Thanks for clarification :)

By Steemit account I meant the default account hold most of the Steem, delegating to new users.

In my example, I should get 2.2 Steem (7.5 / current Steem price).
I get 1.1 as SP, but that other 1.1 is produced as well, right? Does it go to the internal market or where?

In order to give me promise in form of SBD, there needs to be according amount of Steem produced.

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STEEM 0.17
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