The verdict in three sentences
When meeting room billing is rebuilt by hand from a paper diary or a spreadsheet, a large share of out-of-allowance hours never gets invoiced: across 6 rooms, the gap often exceeds 3,000 EUR a month. Coworking software subscriptions cost 100 to 400 EUR a month and fit poorly with tailored deals negotiated tenant by tenant. A custom app for booking, automatic billing and access control costs 3,810 to 6,100 EUR (2,500,000 to 4,000,000 FCFA) on the Kolonell grid, with an 8-week timeline.
Where unbilled revenue goes
The usual set-up in Zuidas: each office tenant has 10 hours of meeting room time a month, extra hours are billed 45 EUR for the small room and 80 EUR for the boardroom, excluding 21% VAT. Reception logs bookings, accounting rebuilds usage at month end. 2026 orders of magnitude for 40 offices and 6 rooms:
| Item | Monthly volume | Unbilled rate | Estimated lost revenue |
|---|---|---|---|
| Out-of-allowance room hours | 216 hours | 25% | 54 h x 60 EUR = 3,240 EUR |
| Bookings by outside clients | 40 slots | 10% | 4 x 250 EUR = 1,000 EUR |
| Printing and add-on services | 120,000 pages | 15% | about 500 EUR |
| Late cancellations not recharged | 25 slots | 80% | 20 x 30 EUR = 600 EUR |
| Virtual office and visitor access | 30 contracts | 5% | about 200 EUR |
| Total | about 5,540 EUR a month |
On top of this come three days of accounting work at each month end and disputed invoices, with no proof of booking.
Subscription software or a custom app
| Criterion | Coworking software subscription | Kolonell custom app |
|---|---|---|
| Cost | 100 to 400 EUR a month (market estimate) | 3,810 to 6,100 EUR once, then maintenance |
| 3-year cost | 3,600 to 14,400 EUR | 5,610 to 7,900 EUR with maintenance at 50 EUR a month |
| Payment by card, iDEAL, SEPA direct debit | usually native | built into the tenant portal |
| Tenant-specific deals | standard plans | free rules per contract |
| Dutch invoicing rules, 21% VAT | yes | yes, with accounting export |
| Access control by badge or QR code | depends on compatible hardware | temporary QR code for visitors |
| Data ownership | with the vendor | database handed to the client |
Above 20 offices, custom becomes profitable from year two, and from year one if you lose more than 1,500 EUR a month in unbilled hours. A Dutch agency would typically quote 25,000 to 60,000 EUR for the same scope (market estimate).
Scope and an 8-week plan
- Week 1: scoping of allowances, rates and approval flows.
- Weeks 2 to 4: online booking for tenants and outside clients, per-room calendar, SMS and email reminders, cancellation rules.
- Weeks 4 to 6: automatic monthly billing with allowance deduction, card, iDEAL and SEPA payment, reminders.
- Weeks 6 to 7: QR code access control, occupancy dashboard.
- Week 8: acceptance with reception and accounting, training, go-live.
Invoicing settings are checked with your accountant against Dutch VAT and e-invoicing requirements during scoping.
Mini case study
Illustrative example: Sanne, manager of a business centre in Zuidas, rents out 40 offices and 6 rooms. She picks a scope at 3,200,000 FCFA (4,880 EUR).
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- Out-of-allowance hours recovered: 3,240 EUR a month.
- Late cancellations and add-on services recovered: about 800 EUR a month on a cautious assumption.
- Accounting time saved: 20 hours x 45 EUR = 900 EUR a month.
- Monthly gain: about 4,940 EUR, minus 50 EUR of maintenance.
Payback: 4,880 / 4,890 = about 1 month.
FAQ
Do tenants need to create an account?
Yes, each tenant company gets access for 1 to 5 users, who see their remaining allowance in real time. Outside clients book without an account and pay upfront by card or iDEAL.
Can we block a room for a multi-day event?
Yes, reception creates long blocks with a specific rate, for example 500 EUR a day. Conflicts with existing bookings are flagged before confirmation.
Do we need new access control hardware?
Not necessarily: a QR code reader at the entrance costs about 150 to 300 EUR. If you already have badge readers, integration depends on their API, checked at scoping.
How are disputed invoices handled?
Each invoice line links to the booking, who made it and the actual entry time. Disputes usually drop by 70 to 80% from the second month.
What does it cost after go-live?
Hosting runs at about 30 to 80 EUR a month and Kolonell maintenance at 50, 110 or 180 EUR a month depending on support level.
Let's scope your project. Send us your number of offices, rooms and allowance plans: we will price a scope between 3,810 and 6,100 EUR deliverable in 8 weeks. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
