BAD Early bound multientity plugin

CalculateTotalAmountEarlyBoundBADPlugin.cs

public class CalculateTotalAmountEarlyBoundBADPlugin : IPlugin
{
    public void Execute(IServiceProvider serviceProvider)
    {
        var context = serviceProvider.GetService(typeof(IPluginExecutionContext)) as IPluginExecutionContext;
        var serviceFactory = serviceProvider.GetService(typeof(IOrganizationServiceFactory)) as IOrganizationServiceFactory;
        var service = serviceFactory.CreateOrganizationService(context.UserId);

        var lateBoundEntity = context.InputParameters["Target"] as Entity;
        switch (lateBoundEntity.LogicalName)
        {
            case Account.EntityLogicalName:
                var account = lateBoundEntity.ToEntity<Account>();
                account.new_totalsum = account.new_netamount + account.new_margin;
                break;
            case Opportunity.EntityLogicalName:
                var opportunity = lateBoundEntity.ToEntity<Opportunity>();
                opportunity.new_totalsum = opportunity.new_netamount + opportunity.new_margin;
                break;
            default:
                break;
        }
    }
}