Dear Vikas,
Arriving at 'Allocable Surplus':
Are you from HR or Accounts? Filling in the Form-A of the PoB Act can be done by someone who has some knowledge of accounting, reading a balance sheet & Profit and Loss A/c and attached schedules. This format starts with Gross Profit, Depreciation, Devpt. Rebate, Direct Taxes, and arriving at 'Available Surplus' which can be extracted from the Profit & Loss A/c & Balance Sheet of your firm. Presumably, you will have to your team of Internal Auditors and Statutory Auditors or Accounts personnel whose assistance is required. Once you understand what's what, then you can do it for other years. I attach a blank format for your reference.
After completion of Form A, you have to fill up Form B, and then Form 'C' & 'D' to complete the formality. An Annual Return in Form D has to be uploaded to the appropriate portals of the Ministry of Labour & Employment. Please use the new revised formats. These forms have to be maintained in the dedicated Registers and shall be shown to the Labour officers as and when asked for. They can be maintained in electronic form also as per Rules 4 & 5 of PoB Rule, 1975.