It started last issue when David Cornthwaite wanted to know what sort of ratio most convenience stores run as a wage percentage against net sales. Well, no point in asking me, so I asked you.
Claire McElhinney owns a Centra which is part of the Musgrave Supervalu Centra Distribution Group of Northern Ireland. She trades in Omagh, County Tyrone. She writes by email: "We work towards a wage percentage of not more than 10% of net sales. Not always easy to keep to at times!
"This is usually higher in holiday times as you're paying holiday pay and also paying for the employee filling in."
And she has the equation, too.
"To find the wage percentage, use a calculator. Divide weekly wage by weekly net sales then hit the percentage button."
And a hint! "As a wee reminder when wondering how to calculate using the two figures, think of doing the impossible, ie, dividing a little number by a much larger number."
Now if only they taught like that at school in my day (and allowed calculators) I might not have scored as such a numbskull.
Redmond Hanlon, who runs The Bakery Stores in Winkleigh, Devon, also put his hand up with an answer. His reply included a bit of history.
"We run a village shop and 20 years ago our wage bill was 4% of net sales; 10 years ago it was 5.5% and today it's 9% (so remarkably similar to Claire's "not more than 10%" observes your reporter). We do pay above the minimum wage; if we didn't then our wages bill would be 7.5% of net sales."
He has pondered the increase. "I think it has been caused by a) the business being more complicated than it used to be; b) the volume of paperwork rising dramatically; and c) my wife working fewer hours than she used to."