hello,
you did right.
you must calculate any cost performed eather goods or services, but its considerd as a primery activity of your firm

good lik,,

I think that either answer is correct. COGS (and Expenses) can be broken down in different ways. Its a question of what is the most useful for you. My understanding is:
- COGS is a contra-Income account to record expenses that can be directly attributable to each sale(ie income transaction).
- Expense accounts are for expenses that cannot be easily attributable to each sale.

Its useful to attribute expenses per sale, so you can see (eg in your P&L) what your gross income is before general expenses are subtracted as a whole. So given the business in question is selling software, they might like to see what expenses happen with each sale, ie COGS. One approach is by general activity, ie the first way, the other by specific activity, ie the second way.

I like the first way:- Cost of Sales are broken into Sales Commissions, Sales and Pre-Sales (expenses), Travel and Accommodation Costs. The assumption is that each of these expenses is directly related to a sale. So this helps show what the income from sales is after these inevitable expenses are taken into account. Cost of Services and Cost of Maintenance completes the costs/expenses for each sale.

The second way simply describes the same thing in more specific detail. Either way is fine by me really. Its a case of personal choice.

Note that general expenses, including general travel, accommodation not directly attributable to a sale, will still be handled in Expenses, ie in similarly named items in there. So you will have:

INCOME
(sub-ledgers of this?)
COGS
- Cost of Sales
- Sales Commissions
- Sales and Pre-Sales Costs
- Travel and Accommodation Costs
- Cost of Services
- Cost of Maintenance
EXPENSES
- Power
- Wages
- (General) Travel and Accommodation Costs (eg to conferences)
- etc - other general expenses