Like Co'den says, it's only £5 for coterminous Scottish certificates, because they don't have to do a separate enquiry for the AWC. If someone in Scotland with FAC applied 2 years later for AWC, they'd still have to pay the full fee, not the £5 fee, because a separate enquiry would have to be performed. There is also no way for someone in the rest of the UK to get a coterminous AWC, because your FAC or SGC isn't been carried out by the Police Service of Scotland and they will have to carry out a full enquiry for the AWC regardless. The AWC system is separate law to the Firearms Acts*, it only applies in Scotland, is only managed through the Police Service of Scotland and the Scottish judicial system. I'm afraid you'll have to pay the full fee irrespective of when you apply.
*And as an aside, while the Firearms Acts apply throughout Great Britain as statute law, their application and enforcement in Scotland is via the Scottish courts and Scots law. That means that caselaw can and does result in variations in the application of those laws and precedents that may be set. There are a variety of examples where this results in differences in hie firearms law is interpreted or enforced in Scotland, one example off the top of my head being when a Scottish court held that Co2 powered airguns were not 'air weapons', leading to a load of issues for paintball operators in Scotland during, from memory, the mid to late 90s. Eventually, the UK government altered statute law to include Co2. This isn't just applicable to firearms law, it's applicable to almost all UK statute law, which normally will include different references, interpretation or sections for Scotland or Scots law, and decisions of the House of Lords, now UK Supreme Court, that apply across jurisdictions having a 'Scots Schedule' to cover application North of the Border. It's been like this for the best part of 300 years, but can still lead to confusion!
