Exactly as described, for the frame loss test, this selects which bandwidth value is used as the test's starting point -- either the profile's own configured bandwidth, the maximum throughput value determined by the throughput test, or the link's maximum line rate, which the description explicitly notes is unsupported. Choosing maximumThroughput here means the frame loss test builds directly on whatever rate the throughput test just measured as achievable, producing a more realistic frame-loss curve for that specific circuit, whereas profileBandwidth simply starts from the SLA-committed rate regardless of what the circuit actually proved capable of. For example, a profile with maximumThroughput selected would automatically start its frame loss test from 950Mbps if that's what the preceding throughput test just measured, rather than blindly starting from the profile's nominal 1Gbps configured bandwidth.