Berkshire Intrinsic Value Calculator question on discount rate

[scorpioncapital]

Does anybody know why if I enter 10% discount rate vs. 50% discount rate, the IV of the B shares changes by about $1000/share?

 

http://www.creativeacademics.com/finance/IV.html

 

I can't believe that a 50% discount rate vs 5-10% makes a difference of only $1000 per B share.

[returnonmycapital]

I would imagine it is due to subsidiary earnings, which the discount rate applies to, being only a portion of the IV calculation. 

 

I suspect the equity investments are a major part of the calculation and are valued at 100%.

[returnonmycapital]

That strikes me as odd.  In my IV calculation I would pay 100% for BRK's float (more likely over 100%) given that it has a negative cost. I would pay 100% for investments that are included in BRK's book value and I would only discount operating earnings of BRK's subs, perhaps for as long as 15 years. I think that is the way WEB would suggest we go about it ourselves, no?

[arbitragr]

I find it unusual that you would use a DCF or a variant of it (Gordon growth model) to value BRK.

Never seen that before on a professional level.