The savings _ from using your "in house" expertise _ in terms of money and man_hours alone, will quickly justify the investment you make in "developing the needed skills" _ especially, when you compare what you spend with the cost of purchasing a commercial software application _ or even engaging the services of an Excel VB developer.
For the purpose of creating custom financial and business management solutions that solve your identified problems, and give you control/ownership, without burning a hole in your pocket, Excel VB offers an amazing variety of possibilities, in the hands of an adequately skilled user.
In addition, an Excel VB developer( who in many cases will tend to be a user turned developer, and is therefore likely to easily see things from your perspective) _ unlike a programmer _ is more likely to be positively disposed to working with you to ensure the application meets your practical needs. S/he will readily understand that the final application is meant to help solve a real problem(s), and will therefore build it to match those expectations.
Spreadsheet Tracking As A Crucial Element For Business Development. There are ways you can use spreadsheets to record and track materials usages/stocks, product sales, and other business data such that discrepancies will be easily detected when they do occur. The use of spreadsheets when properly done, can help to uncover the cause(s) of "losses" in virtually any aspect of a business operation.