I don’t want to get to off topic from Huntsman, but since there’s been discussion about the beam staff in here, hopefully this will still contribute to the conversation. To answer your question, as far as I can tell you did not misread the spreadsheet. However, something about those numbers seemed off from my experience in the game, so I decided to check them out.
Turns out, the beam staff’s “charged beam” does more damage based on how long you’ve been attacking the enemy, ramping up in damage at the same rate (more damage per tick), but capping at a slightly lower point (4 ticks instead of 5), as the regular beam. The values on the spreadsheet give the maximum damage after 4 ticks, but only accurate to Unchained, as both Pyromancer and Battle Wizard passively receive a further 10% buff to ranged weapon damage. This means instead of doing 39.5 damage to unarmoured as the spreadsheet suggests, you do (39.5 * 1.1) = 43.25 damage as these classes.
This, however, also requires you to keep your beam on the same target for ~1.5 seconds before right clicking to do the blast. You also do the damage from having your beam on the target for those 1.5 seconds, which considering they are mandatory to get higher damage on the blast, should be calculated into the damage total. Failure to track your target with the beam for even the smallest of instances will reset this damage boost, however, and you cannot drag this boost over to a new enemy. Each time you swap targets you start again from 0 ticks.
Damage vs. Unarmoured/Infantry
- 0 ticks (instant blast): 22.5 damage (24.5 Pyro/BW)
 
- 1 ticks: (.75) + (22.5 blast) = 23.25 damage (25.25 Pyro/BW)
 
- 2 ticks: (.75 + 1.75) + (28 blast) = 30.5 damage (33.5 Pyro/BW)
 
- 3 ticks: (.75 + 1.75 + 3.5) + (33.75 blast) = 39.75 damage (43.5 Pyro/BW)
 
- 4 ticks: (.75 + 1.75 + 3.5 + 4.5) + (39.5 blast) = 50 damage (54.75 Pyro/BW)
 
- 5 ticks: (.75 + 1.75 + 3.5 + 4.5 + 5.25) + (39.5 blast) = 55.25 damage (60.5 Pyro/BW)
 
Damage vs. Armoured
- 0 ticks (instant blast): 17.75 damage (19.75 Pyro/BW)
 
- 1 ticks: (.5) + (17.75 blast) = 18.25 damage (20.25 Pyro/BW)
 
- 2 ticks: (.5 + .75) + (22.50 blast) = 23.75 damage (26.25 Pyro/BW)
 
- 3 ticks: (.5 + .75 + 1.75) + (27 blast) = 30 damage (33.25 Pyro/BW)
 
- 4 ticks: (.5 + .75 + 1.75 + 2.25) + (31.5 blast) = 36.75 damage (40.75 Pyro/BW)
 
- 5 ticks: (.5 + .75 + 1.75 + 2.25 + 2.75) + (31.5 blast) = 39.5 damage (43.75 Pyro/BW)
 
Hopefully that’s legible for all of you. It’s worth noting it takes about the same amount of time to do 2 instant blasts as it does to wait 4 ticks and the blast (for a maximum damage blast). 2 instant blasts also seem to do about the same total damage as waiting 4 ticks to blast, and generate about the same amount of heat. I’ll let someone else figure out the exact specifics.
The beam staff is already a pretty efficient weapon compared to the Empire Longbow, though. It’s much easier to switch to and from, it affords full freedom of movement while attacking, and it’s rate of fire is much higher. Thus, optimizing it sees a much smaller gain than optimizing the Empire Longbow. Regardless, there are some interesting breakpoints you can reach, but I assume what’s important to one person may not be important to the next. There’s many ways to play the staff, and a certain level of proficiency needed to take advantage of the optimal timings to reach most breakpoints. Also, the crit rate on the staff is through the roof, especially with Pyromancer, so these optimizations matter much less often than on most other weapons.
However, here’s a quick and dirty build, for use with Pyromancer, as an example:
(these are based on rough estimates for damage numbers, not properly calculated or tested in game)
Beam Staff (+5% Crit Chance, +10% vs. Infantry)
Charm (+10% vs. Infantry, +10% vs.  Armoured)
This will allow you to kill both Chaos Sorcerers and a Globadier with two 1 tick body shots (it’s almost impossible not to get at least 1 tick of damage), as well as reducing the time to kill Skaven Armoured specials (but not stormvermin) to a 3 tick body shot from a 4 tick, which should be faster than two instant bursts. It will also allow you to kill a Chaos Mauler in two 4 tick body shots. Unlike the Empire Longbow, the beam staff does have somewhat significant damage falloff with range, so numbers close to breakpoints have a chance not to make them at longer ranges. I’m sure there’s a more optimal setup out there, so feel free to play around with numbers.
If nothing else, hopefully this post highlighted the importance of optimizing traits for some weapons vs. others. It should also give people a better idea as to how the beam staff’s beam mechanics work.