Business Visas

Hi All
I am just wondering if anyone out there can unravel this problem for me.
I have just been to the Myanmar Consulate in Bangkok in the hope of getting a 6 month multi entry Business visa. My understanding is that I would have to exit and re-enter Myanmar every ten weeks or less. I have read that I was eligible for the 6 month visa after having had three previous 10 week Business visas.
The visa section down the side street of the Consulate told me that I needed to go to the Consulate proper on the main street as my Business visas were obtained on arrival at Yangon Airport and not from the Consulate visa section. The difference between a Business visa on arrival and one obtained from the Consulate is an unknown to me still.
Of course when I tried twice to talk to someone in the main consulate area about this specifically, they weren't listening and of course being a foreigner, they just think you are lost and send you back regardless.
There were questions I wanted to ask such as:
With a 6 month Business visa can I enter Myanmar by land at the usual crossings?
Can I exit and re-enter as many times as I like?
Does the 6 month clock stop when I leave Myanmar and start again when I re-enter?
I settled for a 10 week Business Visa in the end as even if I was able to get to the bottom of the 6 month issue it was going to cost about 7,400 Baht.
I had tried to find this information online but maybe it is one of those time when you have to use an agent to get it right, I don't know.
Let me know if you have any experience with this issue, I would love to know for the next time around.
Malcolm