Every unit any Fund owns in the Pool has the same value, but Funds own different numbers of units. The number of units a Fund has is based on the dollar value they have in the Pool. If the unit value is $100, and a Fund adds $1,000 to their Pool balance, the Fund will get 10 more units.
The number of units a Fund owns can only change through deposits or withdrawals from the Pool for that Fund.
The unit value only increases or decreases through gains or losses (real or unrealized gains/losses, interest & dividends). Thus comparing the unit value from start to present can be used as a guide to see the increase (or decrease) of value in the whole Pool.
When adding a new Pool record in FACTS, 100 is used as the initial unit value. This unit value is FIMS-specific and used in the calculation routines for FACTS. The unit value in FIMS is not the same as the unit value from your investment manager's statement. Matching these numbers will not work because the unit value in FIMS will be calculated differently than your investment managers calculations.