Fulfilment centres create business efficiencies but at the same time increase operative complications significantly. EAS automates all sales side reporting, regardless of operations.
Fulfilment centres / 3PLs are referred to often as FBAs despite that being the name for Amazon fulfilment centres. They handle the logistics from warehousing to picking and packing and logistics. Since they are focused on doing only that, they can save you time and money.
Regardless of who is providing the services, storage of your goods in a country obligates you to have either VAT registration, fixed establishment or company registration in that country. Depending on the country and where your company is registered in, you might also require a fiscal representative. Since the fiscal representative exposes themselves to risks, they expect to be compensated for it. Look for a partner who can provide additional services to you also, such as basic accounting.
VAT registration or more significant registration will require you to arrange for at least basic cost side accounting. The paid VAT can be deducted from VATs payable. If the VATs paid exceed the VAT payable, it is possible to claim the VAT back.
EAS provides full sales side data. Shipping from country of the fulfilment centre to the same country is considered to be domestic sales in that country. Shipping cross-border will again fall under OSS VAT scheme. Shipping from the country of your company registration to the country where fulfilment centre is also OSS VAT scheme. EAS automates all of this.