Magento Grandtotal Issue with Incl. Of Tax System and Paypal Tax with discounted price?

[neha_]

I am facing an issue with Magento1.9.2.4. My store is Incl. Of Tax, having 7% tax rate.

Here is the admin panel tax settings screen-shot:

Tax Settings

When I am going to place order with shipping (Incl. of Tax 7%) and Products (Incl. of tax 7%) and coupon discount. The grand total amounts are not what they should be,Like: $p1 = $9.00 $p2 = $86.00 discount =$9.00 Shipping = $10.00

So, Subtotal after discount is : (9+86) - 9 = 86.00 on which the tax will calculate ((86*7)/107)= 5.6262 = 5.63  
Shipping also has 7% tax:
((10*7)/107) = 0.6542 = 0.65 
So the total tax is : 6.28 [to recheck via grand-total incl. of tax ((96*7)/107)] 
and if I add the shipping
to Subtotal after discount = 86 + 10 = 96 
but it is showing 95.99

Which is completely wrong.

Here are cart page screen-shot:

And one more thing is, the same scenario will give different tax of paypal.

I am checking on default Magento no customization.

Paypal is showing Excl. of tax prices but the issue is with Tax amount.