390259 OSC help with order editor mod

Need some help fixing the order editor on my site...its very buggy and needs some focused experienced osc coder to fix... please onyl bid if you have a decent amount of feedback and are willing to see this through to a complete finsih on each of the points below. Chance of lots of other osc work if this goes well. Invoice Editing : When I go into the customers sale invoice in the admin backend and amend the qty/freight etc, then click to email the customer and myself the new amended invoice is very strange looking with odd jumbled codes showing at the at top, need this fixed Invoice Editing When I go and edit the customers invoice in admin back end, If I delete an item, then add another item, and if there is a discount applied... The program does not recalculate if there is a discount what this should be. I did this recently and the customer complained that the amended invoice, firstly looked strange, and the discount was missing off the new items. Small issue but important to avoid disgruntled customers. 4. Invoice Editing Stock issues again with running tallies if stock is added or deleted from the invoice via the edit page. Example : I had to amend the order of in Dec/Jan Judith Ward . I had to delete the red stripe shirt and then I added navy stripe s6 T, checked stock list before then after still qty 3, did not change.. 5. Invoice Editing When editing a order in admin it will not allow me to add a freight price in there. If I highlight the freight tab $10 shows up and when I hit save it goes away again.