Unravelling the detailed story behind the Government's monthly mobile-phone market numbers is not always easy, but the latest figures out this week are more difficult than most. Initially for operators they make depressing reading, with growth in the whole market slowing dramatically during September. In addition, the figures show the more established networks using GSM, D-Amps and CDMA technologies losing customers to the PCS networks launched last year. Despite the pain inflicted by the economic downturn, Hong Kong's mobile numbers had continued to grow in robust fashion. June saw 83,300 new additions, July 62,000 and August 87,000. September's figure, however, slumped to just 24,000 new customers - bringing the market to 2.58 million. This is where analysis becomes tricky. The Office of the Telecommunications Authority (Ofta), which collates the numbers, splits them into only two categories; PCS (which uses 1800 MHz frequency) and services using 800 or 900 MHz which is all the other services, the bulk of which are GSM based. For only the second time, the number of subscribers in this second category dropped. Between the end of August and the end of September the number fell by 34,700. On the other hand, PCS networks added 59,530 subscribers during the same period, for a total of 573,890. On the face of it, the clear implication is that customers from these more established (and generally more expensive) networks have been leaving and joining PCS services. However, this may not necessarily be the case, as nobody trusts anybody else's figures, particularly in the PCS section of the market. SmarTone chief executive Hubert Ng said he thought the PCS market was overestimated in size by more than 100,000 subscribers. 'Many people have two SIM cards (two services), others may have a SIM card but never use it,' he said. His argument is that while companies are counting these customers they are of no value to the operators concerned and should not form part of their disclosed subscriber base. Another factor which may help explain the sudden drop in 800 or 900 MHz users is the once-a-year licensing payment that operators have to make to the Government. An operator has to pay $75 per year, per subscriber in fees to Ofta. If several thousand virtually valueless customers are being held on a company's books just before this payment is due, it makes sense to drop them from the official figures to help cut the payment. Interestingly, Hongkong Telecom disclosed recently it had lost 30,000 customers between the end of March and the end of September. This may help account for the sudden drop, depending on when it decided to report the loss to Ofta. The majority of these, it indicated, were from its no frills 1+1 service, which uses D-amps technology and therefore falls into the 800/900 MHz category. If this theory is true, then the overall market may have not slowed to the extent initially suggested by the figures. When this same sort of hiccup happened in February, both the 800/900 MHz sector and the whole market picked up again soon after. However, there is one incontrovertible assumption to be drawn from these figures; the bulk of the market growth continues to be in PCS. Nobody trusts anybody else's figures, particularly in the PCS section of the market