IRR Calculations

I'm trying to calculate IRR but don't understand the following:

Why does the following set of numbers:

−4000
1200
1410
1875
1050

have the same IRR of 14.3% as this set of numbers:

0
−4000
1200
1410
1875
1050

Surely the 0 for period '0' should cause all the following terms to be discounted or have I misunderstood the way Excel does the calculation?

If anyone can explain this to me it would be massively appreciated!

Cheers,
Nick

I believe that the initial cost of business, -4000, needs to be first in the array calculation. For example, here is what I got from the two IRR statemets:

−4000
1200
1410
1875
1050

IRR = 14%

−4000
0
1200
1410
1875
1050

IRR = 10%

Sound about right?