I doubt very much the figures are deliberately manipulated per se and it seems to smack of desperation for apostates to claim so.
To be counted on the worldwide report you must still be an 'active' publisher, ie, you must have turned in a report for the last 6 months running come the end of the service year. That is still the definition as I understand it and I doubt very much they are flexible with this. At the worst they may count a couple of old publishers who can no longer report any time because of advanced age, senility, etc but who are otherwise faithful.
Instead, what the Watchtower has of course been doing is making it easier and easier to be a 'publisher'. They have in recent years lowered the minimum reporting requirement (now 15 mins for some) and, in what was an absolutely masterful stroke to keep the stats looking good, this year began allowing parents to count time studying with their children. This allows some former 'inactive' parents who never went door-to-door to now put a report in and be counted as 'active' again simply by 'studying' with their children (eg, reading the "My Book of Bible Stories" book to their 6 year old) for at least one hour a month. The latter is what will explain the unexpectedly good publisher increase that will probably be reported this year. This clever little tweak will keep the annual report looking ok for the next few years.
Despite these artificial manipulations to keep the statistics looking decent, there is little doubt that the actual quality of the report and the quality of the published time is reducing dramatically in real terms, at least in terms of bringing new persons into the organisation from the world (although some would argue that spending more time 'studying' with one's children is better quality time than knocking on empty doors in the weekend - they are probably right on that). If the same criteria for reporting time that existed 10 years ago was still applied today the worldwide publisher report would probably be in the negative by now or close to it.
They will of course keep diluting what it means to be a 'publisher' as the years go by and do whatever it takes to keep the annual worldwide report looking respectable short of outright lying. Keeping the organisation looking bright and shiny on the outside is proof that it still has "Jehovah's blessing", and it keeps the donations coming in.