Well, for some reason I couldn't log in my other toons so I did 10 more trials for each macro type.

The same scenario as above.

Total casts = 260 LB's for each of the three "macro types".

Mean Total Damage:

RM - 5759 (8 crits, 10 misses of 260 total)
SM - 5765 (7 crits, 7 misses of 260 total)
CN - 5835 (10 crits, 7 misses of 260 total)

TTest comparison of means were not significantly different between all groups (p-value > 0.05).

Mean DPS:

RM - 170.1
SM - 153.5
CN - 173.4

TTest comparison of means:

RM vs. CN p-value = 0.274
SM vs. CN p-value <0.000001
RM vs. SM p-value = 0.000015

If I remove all trials that had at least 1 miss or 1 crit:

Mean Total Damage (n=# of successful trials of 13 LBs each):

RM - 5884 (n=7)
SM - 5816 (n=9)
CN - 5912 (n=9)

TTest comparison of means were not significantly different between all groups (p-value > 0.05).

Mean DPS:

RM - 173.9
SM - 154.1
CN - 174.0

TTest comparison of means:

RM vs. CN p-value = 0.90
SM vs. CN p-value <0.000001
RM vs. SM p-value <0.000001

So, there is a significant difference in mean DPS between the /castsequence macro (SM) and the /castrandom macro (RM) and simple hotkey (CN) for LB spam. The difference may not seem large but I don't know how it scales at higher levels and with gear/buffs.