Bitman s7 question

I know this will zombie but....

I have some bitmain s7's and was wondering what the percentages were for the pay off

How many do you have? I need an exact number to work with.

I have 3 currently but i plan on buying 4 more this month

At 7 units, you'd pay one off per month or so. As the difficulty increases, that margin increases as well. So you're looking at about 8 to 9 months for a full pay off for them. But this all depends on difficulty hikes and such.

Surprised to see anybody is still investing in mining.

With 7 its actually 2 months.

I was asking about the block discovery fee as 1.5% or 1%. Thank you but i already know the per machine payouts with solo mining or pool mining.
Yes we are still investing, started with a single bitmain s3 and now have several s2's and sp20e's. We are turning this into a business venture since the irs now considers bitcoin property instead of income taxable assets.