All numbers are per student, and assume a class of fifteen students.
Suppose you have an experienced Telon programmer/analyst spending half his time maintaining and enhancing Telon programs, and the other half working on non-Telon programs. You bill him to user departments at $1000/day (or equivalently you bill him at $800/day, but bill the user separately for $200/day of machine time etc. he uses on their behalf). He takes 2 weeks vacation, ten holidays, and one sick day a year, thus working 240 days, 120 of them on Telon programs. Of these 120 days, 60 are spent on analysis and design, 20 on construction, and 40 on testing.
Now this person becomes unavailable (promotion, transfer, retirement, whatever) and you replace him with someone knowing no Telon, asking him to figure it out as best he can. What is the cost? The 120 days/year spent on non-Telon programs, and the 60 days/year spent on analysis and design of Telon programs are largely unaffected as far as the time reporting system sees. Actually he will be making design decisions that do not take advantage of Telon capabilities, but these show up later as slow construction and testing.
Construction time normally triples, so the 20 days/year that the experienced person took now take 60. Testing time only doubles, so the 40 days are now 80. At $1000/day, you and your users are spending an extra $80,000 per year to get the same work done. You will continue to spend this money until he attends a Telon class. The first year, this will be entirely a matter of him doing the work much more slowly as he fumbles around. Not only are you spending the extra $80,000, but he is writing poor Telon code that will be much harder to maintain in future years, so on an accrual basis you are spending much more than $80,000 this year. In subsequent years, you may pay slightly less than $80,000 on his current fumbles, but you are now paying more each year on struggles to maintain poor code written in previous years.
To send him to a Telon class means he must be withdrawn from billable work for four days at a cost of $4,000. The instructor costs $600 per student, and other costs, such as preparation for the class, and rent of a classroom, probably add another $400. The total cost of sending a student to a Telon class is therefore about $5,000, 80% of which is the cost of the student's time, 12% is the cost of the instructor, and 8% is miscellaneous.
If an investment of $5,000 will return you $80,000/year, that is an ROI of 1,600% per year. Few investments do better than this.