Max_Burst_Size calculation

Hi Group,

I'm trying to understand how to calculate the Max-Burst-Size in the CM-configfile.
For that I took some specification RFI,DRFI,DVB and some cisco-pages and what
I could find in the web.

So what I figured out is the way to calculate the upstream-max-burst-size:

Assuming Modulation is 16-qam and Minislotsize 4 (Symbolrate=64)
= 4 (Bits_per_Symbol) * 64 (Symbol_Rate) = 256 (Bit) / 8 = 32 (Byte)
= 255 (max_minislots) * 32 (minislotsize_in_byte) = 8160 (Max_Burst_Size)

Assuming Modulation is 64-qam and Minislotsize 4 (Symbolrate=64)
= 6 (Bits_per_Symbol) * 64 (Symbol_Rate) = 384 (Bit) / 8 = 48 (Byte)
= 255 (max_minislots) * 48 (minislotsize_in_byte) = 12.240 (Max_Burst_Size)

What I can't figure out was how to calculate the downstream-max-burst-size

Things I know:
Roll-off-factor: 0,15 (1+alpha = 1,15)
Channelwidth: 8 MHz
Symbolrate: 6152

Calculation of the Channelwidth:
Symbolrate * (1+Roll-off-factor)

=6952 (Symbolrate) * (1+1,15) (1+alpha) = 7994,8

Throughput calculation:

assuming Modulation is 64-qam
6952 (Symbolrate) * 6 (Bits per Symbol) * 188/204 (Reed-Solomon-Coding) = 38,44

assuming Modulation is 256-qam
6952 (Symbolrate) * 8 (Bits per Symbol) * 188/204 (Reed-Solomon-Coding) = 51,25

I hope someone could verify my calculations and can give me a hint in calculating the
DS-max-burst-size.

Thank you,
regards

Benedikt