Ok, did a small amount of testing.

Scenario: L60 Draenai Shaman, Naked, No Talents, Had some 1% to hit buff the whole test time (not sure where it was from)
Cast Rank 10 Lightning Bolt at the L60 Target Dummy
I used Recount to calculate the Total Damage and DPS etc..

Macros:
1) /castrandom Lightning Bolt, Lightning Bolt, Lightning Bolt, Lightning Bolt, Lightning Bolt - I will call this RM
2) /castsequence Lightning Bolt, Lightning Bolt, Lightning Bolt, Lightning Bolt, Lightning Bolt - I will call this SM
3) just Lightning Bolt place on Hotbar - I will call this CN

Performed 10 trials for each macro. I spammed the key as consistent as I could, quite quickly (this is a variable however). I remained the same distance from the dummy each trial.

With my mana I was able to cast 13 LB's every time

Mean Total Damage (n=10)
RM - 5638.1
SM - 5800.2
CN - 5862.4

TTest (2-tailed) comparing mean Total Damage between RM and SM to CN and RM to SM (sorry I don't have ANOVA - or at least I don't know where it is in OpenOffice)

P-values
RM vs CN - 0.13
SM vs CN - 0.60
RM vs SM - 0.32

Total Damage was not significantly different. This is expected and indicates I can keep all data in the analysis (includes Crits and Misses).

Mean DAMAGE PER SECOND (DPS) (n=10)

RM - 166.12
SM - 154.92
CN - 172.49

TTest comparing mean DPS between RM and SM to CN and RM to SM (sorry I don't have ANOVA - or at least I don't know where it is in OpenOffice)

P-values
RM vs CN - 0.16
SM vs CN - 0.000022
RM vs SM - 0.026

There was a significant difference in mean DPS between the Castsequence (SM) Macro and the Castrandom (RM) Macro and Standard straight casting hotkey (CN). There was not a significant difference between RM and CN.

I will do some more testing later on and exclude all trials that have crits and misses. If I exclude them I lose half the data, but the p-values for the mean DPS become 0.000035 and 0.000038 for the SM vs CN and RM, respectively; while the mean total damage remains not different.

Out of 130 LB's:

RM - 1 Crit, 5 Misses
SM - 5 Crits, 3 Misses
CN - 5 Crits, 3 Misses