Salary negotiation after accepting the job?

[b]BLUF, in two-parts:

A. Is it wrong / bad form to attempt internal salary negotiations after the job has been accepted?

B. If not, what is an appropriate method to broach / handle this discussion?[/b]

I was recently offered (and accepted & am looking forward to beginning) the manager role of a different team within our company.

During the interview process, I spoke with the man who will be my new boss. Our company works on a grade-system-by-twos. I am currently a Grade 32. The manager position will be Grade 38.

When we first spoke, we were talking about a completely different job in which the boss said "Oh, the tech support gig is steup so that there's a 4% increase and then a 3% for going to Senior in that role." Basically a tech support would be Grade 32. To become a senior tech, they'd go to Grade 36 so the company would give them 4% for the first two-step grade jump (32 to 34) and then another 3% for the next two-step (34 to 36.)

I'll be going from 32 (to 34, to 36 and then ultimately) to 38.

The HR rep has said they will be giving me a 10% raise (for going from 32 to 38) and then a pro-rate 2.7% merit increase.

I'm thinking that I should be getting at least 11% as the base increase rate.

32 to 34 = 4%
34 to 36 = 3%
36 to 38 = 4%
Merit = 2.7%

The difference between the 10% and 11% is only about $750 and I don't want to look like a schmuck trying to finnagle another few pennies out of the company (especially on the heels of two memos from the CEO about penny-pinching measures we're taking.)

However, even at the 10 or 11%, my end result pay rate is barely above the 25% mark of Payroll Managers in this area. Salary.com shows a delta of about $23,000 between the 25th and 75th percentiles. In that bell curve, the peak would be about $10,000 more than either the 10% or 11% mark.

The other thing that concerns me a bit is that they're talking about a flat 10% rather than the compounded method the boss previously mentioned. By using the flat 10% instead of 4% + 3% + 3%, they're saving another $250 a year.

$1,000 a year may not seem like much and by all rights, it's really not a whole lot. I know that. I don't want to cut off my nose to spite my face here.

Ideally, I'd like to go back to the boss and say "I spoke with the HR rep and she indicated X salary based on 10% and 2.7%. That seems low for this job in this area. I was expecting more along the lines of X plus $4,000 or $5,000."

And then, if he says "Gee, would love to however we're in a downturn and we'd rather not have to lay someone off to cover your salary" (in essence) or "Gee, that's great but you're a new manager in this company" I could at least fall back to the basics of what we'd covered before ...

"I understand and appreciate that. I want to do my part as a stockholder to help the company thrive however, the basic numbers we previously discussed certainly support X plus $1,000."

Thoughts? Suggestions? (And feel free to be totally honest!)