McKendrick. Contract Law: Text, Cases, and Materials (2018 8 ed). p 752.
An infamous example of this is provided by the case of Arcos Ltd v. E A Ronaasen and Son  AC 470. The parties entered into a contract for the sale of timber staves cut to a thickness of 1/2 inch. The purchasers alleged the sellers had breached the contract as the staves were of the wrong thickness, being 9/16 of an inch thick. The House of Lords held that the purchasers were entitled to reject the timber. Lord Atkin stated (at p. 479) that:
If the written contract specifies conditions of weight, measurement and the like, those conditions must be complied with. A ton does not mean about a ton, or a yard about a yard. Still less when you descend to minute measurements does 1/2 inch mean about 1/2 inch. If the seller wants a margin he must and in my experience does stipulate for it.
The buyers were held to be entitled to reject the timber notwithstanding the fact that their motive for trying to get out of the contract was that it had turned out to be a bad bargain for them as a result of a fall in the market price of timber. The House of Lords were aware of the reasons for the buyers’ wish to get out of the contract but were of the view that they were irrelevant.
Pretend that Atkin had commenced with inch first. Then in the sentence beneath, would 'still less' become 'still more'?
1/2 inch mean about 1/2 inch. Still ? when you ascend to larger measurements do a ton does not mean about a ton, or a yard about a yard.
I read the OED :
much less (also far less, still less): used to characterize a statement or suggestion as still more unacceptable or inapposite than one that has been already denied.