Dear mgourley,
As per previous post / my checking, yr vinegar is pretty potent, not designed for Fish and Chips.!
Yr query was -
Is there any cost/benefit to using acedic acid and diluting it vs. using processed 200 grain vinegar and more elbow grease?
So the query is cost/benefit of (conc. [glacial] acetic acid + water + inconvenience) vs cost (20% vinegar)
(conc.acetic can be nasty to handle IMEX but I would imagine 20% is not too user-friendly either !)
For equal concentrations, the benefit will presumably be identical, ie elbow grease the same (and in fact desirable according to comment below).
Technically a few other items are related to a meaningful evaluation, eg –
(1) Criteria for acceptability, eg final cleanliness / sanitary (micro) status
(2) Optimum concentration of acetic acid to achieve (1)
I didn’t find any detailed analysis of performance vs concentration from a quick net look. perhaps you have validated this already ?
Different sources seem to have varying opinions on uses of acetic acid. Some focus mainly as cleaners, others as sanitizers, eg see later below (not specifically for bakeries). No direct experience myself.
CDC (2008) has a low opinion of vinegar’s micro.activity (maybe a question of conc. also) –
Some environmental groups advocate "environmentally safe" products as alternatives to commercial germicides in the home-care setting. These alternatives (e.g., ammonia, baking soda, vinegar, Borax, liquid detergent) are not registered with EPA and should not be used for disinfecting because they are ineffective against S. aureus. Borax, baking soda, and detergents also are ineffective against Salmonella Typhi and E.coli; however, undiluted vinegar and ammonia are effective against S. Typhi and E.coli 53, 332, 333.
(my underline)
Used in Cleaning
Acids: Good for cleaning alkali soils and removing minerals, especially calcium and magnesium, can condition water. There are two types:
• Inorganic — strong and corrosive, not recommended for food plant use. Examples are phosphoric acid, hydrochloric acid, and sulfuric and nitric acids.
• Organic — most useful in food plants as they are not as corrosive. Examples are acetic acid, tartaric acid, and lactic acid.
Once the chemical has been applied to the surface, it will require contact time to penetrate and break up soil, but not so long that it begins to dry. Use mechanical action as needed to remove soil and prevent buildup that can contribute to biofilm formation. As a rule, scrub contact surfaces on a daily basis and indirect surfaces such as frames at least once a week]. Unfortunately, some chemicals are represented as “no-scrub” and touted as being effective without mechanical action. Experience and scientific data have shown that scrubbing is required to prevent the formation of biofilms. Scrubbing, however, should not be so intense as to cause scratches or gouges in the surface being cleaned as these then become harborage niches for bacteria and biofilms may begin to form. In this instance, softer scrub pads or soft bristled brushes may be a better alternative to “green pads”
Used in Sanitising
Acid Sanitizers
Acid sanitizers can combine the rinsing and sanitizing steps. Organic acids such as acetic, peroxyacetic, lactic, propionic, and formic acids are the most common acid sanitizers. The acid neutralizes residues of alkaline cleaning compounds, prevents alkaline deposits from forming, and sanitizes. These compounds work very well on stainless-steel surfaces or where they may be in contact for a long time. Automated cleaning systems in food plants often combine sanitizing with the final rinse. This has made acid sanitizers popular. Acid sanitizers are sensitive to pH changes, but hard water reduces their effectiveness less than iodine-based sanitizers.
Heavy foam used to make it difficult to drain acid sanitizers from equipment, but nonfoaming acid sanitizers are now available. Acids are not as efficient as irradiation, and at high concentrations they can slightly affect the color and odor of foods such as meat. Also, acetic acid does not seem to destroy Salmonella bacteria.
Peroxyacetic acid is a rapid sanitizer that kills a wide variety of microbes and is used in food processing plants. It is less corrosive than iodine and chlorine sanitizers and causes less pitting of equipment surfaces.
You might find the attachment in this post also of some interest although somewhat different orientation -
http://www.ifsqn.com...5643#entry75643
Rgds / Charles.C
PS - if you have a lab., high grade glacial acetic will probably be cheap as previous post but it obviously depends on cost of the shelf 20% and yr staff liking of acetic fumes. 
PPS - I noticed that a 10min soak in the 20% will also cure Athlete's Foot. I wouldn't like to validate that one.