DRG In Delve/Plasm Farm?

The entirety of FFXI's combat system is incredibly simple to replicate using basic algebra. Those of us who bother taking the time to code a program to do that call those programs simulations, as they're simulating the game to the tiniest detail, even though most of those details are irrelevant to actual comparisons. For comparing jobs to each other, pieces of gear, entire gearsets, changes in conditions, etc., a true simulation is unparalleled for accuracy; accounting for human/operator error is impossible and can not be blamed on the simulation or its creator, and the results remain the same regardless. These types of mathematics produce absolute answers, you can not question or argue against a number that is hard coded into the game.

Spreadsheets do the exact same thing in a more compact form at the expense of some features in most cases. Their relevancy remains the same, however: you can not argue against cold, hard mathematical facts just on the basis of feels or because of human error. If X job is mathematically superior to Y job, the method used to represent that in numbers does not change the validity of the conclusion. Spreadsheets use the exact same math as simulations, they just don't always have the ability (easily, anyway) to change certain variables or simulate some other variables without becoming unwieldy or becoming actual simulations. Those variables are almost always certainly never going to change the end result of a comparison, they'll just reduce the accuracy of a result in terms of what you get out of your spreadsheet compared to what you'd see in the actual game by a few DPS, but that impacts every job equally.

Parses are a terrible way to compare anything unless you're comparing data gathered over a long period of time, they function best as tools to collect research data or to compare yourself to others around you and see who needs to be kicked from an alliance for not pulling their weight.

Numbers are easily abused by people who don't understand what they mean or their purpose. People look at a parse or a spreadsheet and when they don't understand the inner workings, they just go WELL THIS NUMBER IS LARGER!

Well, unfortunately that's not exactly how things work. A spreadsheet can tell you the maximum long-term limit average that a (semi-*)ideal player can achieve in a specific constructed circumstance.

In reality, any given player will only achieve some fraction of the ideal capacity in an ideal situation. There are a lot of things that factor into this: reaction time / reflexes, attentiveness, speed at which the player engages, aggressiveness, anxiety, computer quality, connection speed, ambient temperature, offspring, time in milliseconds since offspring last pooped, use of and/or quality of spellcast, current position in hormonal cycle of female significant other, number of times male significant other has previously masturbated on the current day, time in milliseconds since last cigarette, serum insulin levels, local population density of Anelpistarachne paichnididiakopi spiders, combustibility of pet goldfish, efficiency of macro setup, responsiveness of keyboard, probability that one will engage in oral sex during the event, just sucking in general ...

And there are really no ideal events and only complex simulations can accomodate the odd constraints that might be present to varying degrees, so really in practice you're always looking at a lower number than what you predict. A spreadsheet is meant to tell you what gives you the best chance.