How much difference if the tonearm is mounted 5mm

Let me make it clear. When i mounted the arm as the manufacture suggested, 212mm STP, the cartridge could not reach the cross point on my Dr. Feickert NG Protractor (I extended the cartridge all the way out from the Pivot) it was 4mm short. Unless i have a longer head shell or i will have to mount the arm 4mm closer than spec. (5mm to be sure).
If I mount it closer, and use the Protractor to align the cartridge, will the arm be performed as normal?
Thanks to all who have responsed so far.
Calvin

Hi Stringreen,
I am adding a second arm on my turntable. My turntable came with the JMW 10, so the armbase does not accomodate with the new arm wand. I have to change the whole set to the 3D, a bit expensive right now.
As fir the new arm, it is shorter than spec. Hence the question.
Thanks,
Calvin

Hi Bifwynne,
Yes, that was the one I use to set up the cartridge at first. I also checked the leveling of my table and armboard. As of right now, i beleive that the arm is deffected. It was made shorter than the specs by mistake.
Thanks,
Calvin

Good morning,
Thanks to all of you who have answered to give advises in this matter. Yesterday, I mounted the arm 5mm shorter than manufactor reccomedation. The result was terific. I will run it for a few days to breaking in and will report back. In the mean time, does anyone know is there exists any head shell which has the mounting distance further than normal? All I can find is the Ortofon LH 9000 and the zyx headshell. I an leaning to the zyx but it is too expensive (700 retailed). How effective of a good design headshell soundwise?
Thanks
Calvin

I will order the ZuPreme,
Thanks to all of you.
Calvin

Hi Lewn,
Your response totally makes sense to me. Here is what had happended.
when i mounted the tonearm 212mm S2P the cartridge could not reach the crossmark on the Dr. Feickert Protractor, it seams like the slots are too short. Two days ago, I mounted it at 207mm, the cartridge can touch the crossmark now, but the offset angle is off at about 20 degree to get allignment correctly. As of now, all i can think of is the arm problem since I have used the Protractor before with the Vpi jmw and the Triplanar vii u2 with no problem at all. Please give me your opinion.
Thanks, and I used Baerwald, i will try Stevenson to see if it is any better.
Calvin

Hi Rauliruegas,
i mounted the tonearm 5mm closer (pivot to spindle, not pivot to stylus), and used the Feickert protractor to mount the cartridge. Therefore in theory, if I understood it correctly and if we could trust the Feickert tractor, the cartridge was mounted in the right geometry figured out by the maker of the protractor. Am I right?
The only thing which is bothering me is, although the arm cartridge combnation peformed correctly, it will not get out all of its potential which the designer put onto the arm. Also, the offset angle is off at arround 20 degree make me worry for the pivot bearing.
I hope it makes sense.
Thanks,
Calvin

Hi Lewm,
I am confused. On my Feickert protractor, there are 3 different geometries for alignment, S, B, and L. Could i use it to align with Stevenson or the tractor is only acurate for only the Baerwald?
Thanks,
Calvin

Gentlements, please.
I have learned a lot from all of you since the thread initiated. 
Thanks,
Calvin

Hi everyone,
I am wondering based on the chart about the comparison between the 3 alignments B, L, and S. The Stevenson looks the worst. Why there are still designers used this geometry for their tonearm?
Thanks,
Calvin