A transactional memory (TM) receives an Atomic Metering Command (AMC) across a bus from a processor. The command includes a memory address and a meter pair indicator value. In response to the AMC, the TM pulls an input value (IV). The TM uses the memory address to read a word including multiple credit values from a memory unit. Circuitry within the TM selects a pair of credit values, subtracts the IV from each of the pair of credit values thereby generating a pair of decremented credit values, compares the pair of decremented credit values with a threshold value, respectively, thereby generating a pair of indicator values, performs a lookup based upon the pair of indicator values and the meter pair indicator value, and outputs a selector value and a result value that represents a meter color. The selector value determines the credit values written back to the memory unit.