❝ An independent garage group in Manchester runs three sites and 22 technicians on £4.8M of turnover. Labour is quoted from a published times guide and charged at £85 an hour. Technicians clock on and off every job, so the actual time is recorded, and nobody compares the two numbers. Across 19,400 jobs a year, 24% overran their quoted time by an average of 0.6 hours. That is 2,794 hours worked and never billed, worth £237,000. The design below calculates the variance nightly, reads technician notes to classify why each job overran, and alerts the service advisor while the car is still on the ramp. The agent costs £190 a month.
A Vivaro came in for a clutch. The times guide said 2.9 hours, so the customer was quoted 2.9 hours, and the job card was written for 2.9 hours.
It took Marcus 5.4. Two of the gearbox bellhousing bolts had corroded solid and one sheared, which is ordinary on a van of that age and mileage in the north of England.
The customer was invoiced 2.9 hours. Nobody made a decision about that. The invoice was generated from the quote, because that is what the system does, and the 2.5 hours Marcus spent on the seized bolts left no trace anywhere except his clock-off time, which nobody reads.
The business
Three sites across Greater Manchester, 22 technicians, £4.8M turnover, split between retail servicing, MOT work and a growing local fleet contract book. Around 19,400 jobs a year.
The stack is standard for an independent of this size. A DMS holds job cards, quoted labour times, parts and invoicing. Technicians clock on and off jobs on a workshop terminal, so actual time against job number exists as data and has done for six years. A published labour times guide supplies the quoted figures. Xero takes the invoices.
Everything needed to spot this problem was already being recorded. That is the part worth sitting with.
What is actually going wrong
Ray, who runs the Oldham site, would tell you he knows which jobs run over. Ask him which, and he will name diesel injector work and anything on a French van, and he is right about both.
He is right about the two he can remember. There were 47 job types running consistently over quote, and the pattern in most of them was invisible to him because each individual instance looked like bad luck. One seized bolt is bad luck. Two hundred seized bolts across a year on the same three vehicle platforms is a quoting error, and it only becomes visible when somebody counts.
Nobody counted, for an ordinary reason. The variance calculation requires joining quoted hours from the job card to clocked hours from the workshop terminal, per job, across 19,400 jobs. In the DMS those live in different places and there is no report that puts them side by side. Getting the number meant exporting two files and building a spreadsheet, and the person capable of building it is also the person running three workshops.
So the group priced 19,400 jobs a year from a book, and never once checked the book against its own workshop.
What it costs
24% of jobs overran their quoted labour time, by an average of 0.6 hours. That is 2,794 hours a year worked and not billed. At the £85 retail rate, £237,000 of labour revenue.
For scale, 22 technicians sell roughly 35,000 hours a year, so the leak is about 8% of labour revenue. The group's net margin that year was 4.1%.
The second cost is quieter. Because overruns were absorbed silently, the technicians most likely to hit them were the ones taking the awkward jobs, and their efficiency figures looked worse than the technicians cherry-picking clean services. One of them was performance managed over it.
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