Network Scheduling / Unnecessary float / Both forward and backward schedlng
I have an issue with the creation of network
We create transactional network through standard network adn their linkage with materials. The network has lot of activities, some sequences are backward scheduled and some are set for forward scheduling. We also provided constraints for the first and last activity. So the network start date adn end date are fixed. However when the network is created using this standard network, float is getting accumulated activities while we need the float at some other activities.
One of the activities in teh backward scheduling has some successors to it, which are decided by forward scheduling. Here my team say that this is the problem, and say that either the whole NW can be backward scheduled or forward scheduled. Is it correct. Why is the dates incorrect with unnecessary floats (though the sequence is correct)