Conceptual query on valuation-financial reporting

please can anybody help me out in understanding- While valuing share under NET ASSET METHOD, we calculate Intrinsic value per share fully paid up. and in order to find the value of a partly paid up share we substract the unpaid amt. of the partly paid up share from the VALUE OF FULL PAID UP SHARE.

MY QUESTION IS WHY dont we simply calculate the value of partly paid up share by multiplying the intrinsic value with the paid up value of partly paid up share.

Please comment using the given data:

Intrinsic value per share- Rs.23 per share fully paid

Now what will be the value of 1 partly paid share of Rs.10, Rs. 8 paid up.

will it be 

230-2= 228

or

23*8=184

which answer is correct.

Please answer it with explanation.........

Thanks in advance