In order to obtain the initial Entry Clearance, you need to show that you have £200,000 funds either in cash in a bank account, or available to your business of which you are a Director. If you have invested part of the funds in the UK business within 12 months of the date of application, the part invested can be counted towards £200,000. The funds of £200,000 need to be fully invested in the business before your extension application, which is within the 3 years and 4 months of the initial period of leave. You don't have to deploy the full amount at once. However, you need to show that you have £200,000 available to you throughout the initial period of leave. For example, if you have invested £50,000 in the first month, you need to show another £150,000 available to you. If the business only spent £150,000 at the time of extension application, the outstanding amount of £50,000 must be either invested in the business by cash, or share capital, or unsecured and subordinated director's loan. I suggest you seek legal advice before or immediately after obtaining the Entry Clearance application to ensure that you have maintained and spent the funds as required by the Home Office.
