John Vicars is talking when his computer screen causes distraction. "Oh, it's just come through there with regards to the game tomorrow with Birmingham City," he says.
The timing is good. Vicars, the operations director at Derby County, is talking about direct ticket pricing, when the direct ticket pricing system effectively starts talking to him.
Buying a ticket for a Derby County game, you see, is not like buying a ticket for the vast majority of football clubs in this country. It's actually more like buying a flight, or a ticket to the theatre.
If you leave it late, you're taking a gamble, especially for the big games. At Pride Park, you could have bought a single ticket for the final game of the season against Millwall before a ball had been kicked in August. That is not the norm.
Traditionally, a football fan can buy a season ticket or do it game-by-game. In recent years the half-season ticket has increased in popularity.
At Derby, you can get either of those, or a six- or four-game bundle, and the key here is, what goes in that bundle of games will be the Derby fan's choice, a kind of pick-and-mix with football matches.
"Eighteen months or so ago we saw the effects of the economy on attendances, not just at pride Park but across the board," he adds. "We did a couple of experiments where we lowered drastically the price of tickets down to around £10 and we saw a tremendous pick up in sales. From that we got the view that in an ever challenging economy, there was a price point people were prepared to pay and one they weren't.
"We wanted the flexibility to alter prices for every game, but not upset the season-ticket holders who pay for they tickets in advance. I went to the States and spoke to the San Francisco Giants, who were the first sports team in the world who took the Digonex dynamic pricing model. It had been used in airlines and hotels for years. They brought Digonex's software into baseball. I spent time there and in Minnesota with the basketball team.
"It really appealed to me, in the laws of supply and demand, the ticket price fluctuates. Secondly, you inform the season-ticket holder not to think about their season ticket as dividing it by 23. We have categorised the games for years, gold and silver or whatever, so we explained all 23 games were not priced the same to start with. The pledge we made was we would never sell a ticket lower than you paid for it.
"The Tuesday night games struggle to sell to a Saturday attendance level. Most people with season-ticket packages realised they're reasonably cheap. The season-ticket holder is paying around seven or eight pounds for that seat. That gives us the ability to start prices at nine or 10 pounds.
"At Derby we put all our tickets on sale at the beginning of the season. If you want to get a cheap return ticket to Malaga, when the prices come out and you get in early they are usually cheap. If you leave it until the day before you're probably going to pay top dollar. That is the system."
The Football League has given Derby dispensation to let them trial the Digonex system (usually you can only alter the prices for four games per season) and they pay the American company an annual fee for their software.
Cardiff have followed. Bristol City are considering it. Two Premiership rugby clubs are about to use it and big European clubs, for whom the model will be better suited (last minute pricing for a big game will go up) are keen to use it. The model is used increasingly through American sport. Significantly, none who have trialled it have gone back to the old fashioned model of how to sell tickets for sports events.
"People always ask about the weather," Vicars says. "We are taking into account all factors. If we got three or four inches of snow and it was pretty unpleasant, with this system, we have the ability to adjust ticket prices downwards. I know what the local market will and won't stand.
"The system reports to us on a daily basis and recommends increases or decreases. I can override that. If it comes up at 75 quid for the Nottingham Forest game, I can override that!"
Derby are 13th in the Championship. Their average attendance is the third best in the division, but then it was last season. Impressively, no attendance has dropped beneath 20,000 for a league game this season. They expect to top 22,000 tomorrow teatime for the visit of Birmingham City.
"Birmingham on Saturday, for a televised game (that knocks attendance) in our category E, tickets are currently £16 for adults and £4 for under-18s," adds Vicars.
Twenty pounds for a dad and his son to watch a Championship derby? Sounds reasonable, but you had better be quick, it might change.