With such changes, the Scottish executive estimated that the scheme would cost £50 million.
Such a scheme would only cost £13,000, and the work went on for many years.
Costings at November 1991 prices suggest that the scheme will cost in the region of £1.3 million.
Prosecutors said the second scheme, which lasted from 1988 to March of this year, cost the city $776,000.
Investigators say the scheme cost the city $160 million in lost tax revenues in the last four years alone.
The new teachers' scheme should cost no more than 20.1% of salaries, with staff paying 9.6%.
By the time of its completion in 1772, the scheme had cost £24,000.
The scheme had cost £361,484, of which £221,350 had been borrowed, while the rest came from company resources.
Initial estimates suggested that the scheme would have cost around £500m.
The scheme, with its first three survey phases now complete, has cost £6.3m over the past six years.