Axis2 Performance Issue

Hi,
I have a strange issue with performance evaluation using Axis2 middleware. I have two scenarios of calling web services through a client. One in centralised fashion and the other in decentralised fashion. Centralised scenario 1 goes like this: I have a client that dynamically invokes 5 different services in a workflow fashion. I have engaged a custom module as inflow handler to the 5 different services. I calculate the performance evaluation of calling these 5 services with the engagement of my module as well as without engaging the module. When I call these services through the same client as a workflow, without my custom module then it takes 1912 milli seconds. However, when I engage my custom module to the services it takes 2070- milli seconds. This shows the performance overhead of my custom module equivalent to 160 milli seconds.
The second secnario 2 of decentralised invocation of the same services goes like this:A client invokes the first service of the 5 different services. Then the first service invokes the second service and similarly the sequence goes to the invocation of service 5 through the service 4. These services are invoked asynchronously (withoutout blocking) as a workflow. These services perform their own functionalities like in the earlier scenario, however, they are playing the role of a client for the invocation of the next service.Now the performance I get with the engagement and without engagement of my custom module goes like this:Without engageing the module it takes ~ 1450 milli second, which is less than 1850 as was the case in scenario 1, because they are invoked in decentralised fashion and hence no centralised bottleneck.But when I invoke this decentralised invocation with the engagement of the same module, it takes more than 2094 milli second. which shows that the module I have engaged is taking more than 600 milli second. I am wondering this module is the same as was engaged in scenario 1 and it took 160 milli second.  However, here it takes much more (~ 600 milli second) compared to the centralised one. Can one kindly guide me through where and what the reason might be?
regards,
Sardar Hussain