Dear Pradeep,
The two different ways of calculating CTCs quoted in your post are two extremely different ways of looking at the concept of CTC. Treated as an HR term, CTC is very much what you say it is - "Fundamentally what we spend to retain a person." I believe it should continue to be kept so as it has become a normally used phrase by HR today and should not be confused with anything else.
Having said this, I think I should also mention that CTC (Cost to Company, irrespective of the resource or department applied to) is basically a finance term and literally means the Cost to a company in getting a thing done. The "thing" could begin with any of the smallest function or sub-functions in a company. For example, the cost to a bank in processing a loan will include various aspects like administrative expenses, lawyer charges, communication expenses, prospecting expenses, sales personnel expenses, consultation expenses, conveyance, and time of executives, and so on.
Similarly, in corporate finance terms, an employee is one unit of a resource (human) applied for achieving a resultant objective. Let's call this objective "X" for now. So, all the resources applied in order to achieve the "X" objective together form the CTC to the company to achieve that objective. The calculation of this varies with the finance policies followed by companies.
For example, for a Sales Executive's profile, where the job is to achieve Rs. 100,000 of sales, the cost to the company in achieving that Sales turnover will realistically include his gross remuneration + all the expenses that you mentioned in your post. And if the total CTC here becomes more than Rs. 100,000, the Human Resource (Sales Executive) is a big loss to the company and not worth investing in. In fact, to get a financially realistic value of the costs, some companies even include opportunity costs like the cost of leave (of any kind) taken, the cost of results not achieved (in comparison to a performer in his place), and so on to calculate the value of CTC.
However, as I said before, the term CTC has become more of an HR term today used in a particular context within a specified scope, and so it must be retained with a fair degree of standardization across employers everywhere.
I hope this clears your query.
Regards,
SKN