diff --git a/examples/TSVtoSIE.php b/examples/TSVtoSIE.php
index 72b592f..60125e7 100644
--- a/examples/TSVtoSIE.php
+++ b/examples/TSVtoSIE.php
@@ -99,7 +99,7 @@ public function parseBalance(string $value, Company $company, FiscalYear $fiscal
             // account - try fetch it from the company
             $account = $company->getAccount($data['account_id']);
             // account not found? create it.
-            if (! $account instanceof Account) {
+            if ($account === null) {
                 $account = (new Account($data['account_id']))
                     ->setName($data['account_name']);
                 $company->addAccount($account);
@@ -172,7 +172,7 @@ public function parseTransactions(string $value, Company $company, int $skipHead
 
             // account
             $account = $company->getAccount($data['account_no']);
-            if (! $account instanceof Account) {
+            if ($account === null) {
                 $account = (new Account($data['account_no']))
                     ->setName($data['account_name']);
                 $company->addAccount($account);
@@ -189,13 +189,13 @@ public function parseTransactions(string $value, Company $company, int $skipHead
             if ($data['result_unit'] !== '') {
                 // find dimension (pre-defined)
                 $dim = $company->getDimension(Dimension::DIMENSION_COST_CENTRE);
-                if (!$dim instanceof Dimension) {
+                if ($dim === null) {
                     throw new \LogicException('Expected to find dimension: DIMENSION_COST_CENTRE');
                 }
 
                 // find / create object
                 $object = $dim->getObject($data['result_unit']);
-                if (! $object instanceof DimensionObject) {
+                if ($object === null) {
                     $object = (new DimensionObject($data['result_unit']))
                         ->setDimension($dim)
                         ->setName('Resultatenhet ' . $data['result_unit']); //We don't have this data, so just set it
@@ -210,13 +210,13 @@ public function parseTransactions(string $value, Company $company, int $skipHead
             if ($data['project'] !== '') {
                 // find dimension (pre-defined)
                 $dim = $company->getDimension(Dimension::DIMENSION_PROJECT);
-                if (!$dim instanceof Dimension) {
+                if ($dim === null) {
                     throw new \LogicException('Expected to find dimension: DIMENSION_PROJECT');
                 }
 
                 // find / create object
                 $object = $dim->getObject($data['project']);
-                if (! $object instanceof DimensionObject) {
+                if ($object === null) {
                     $object = (new DimensionObject($data['project']))
                         ->setDimension($dim)
                         ->setName('Projekt ' . $data['project']); //We don't have this data, so just set it
diff --git a/rector.php b/rector.php
index 9eb4e30..d872222 100644
--- a/rector.php
+++ b/rector.php
@@ -2,6 +2,7 @@
 
 declare(strict_types=1);
 
+use Rector\CodeQuality\Rector\Identical\FlipTypeControlToUseExclusiveTypeRector;
 use Rector\Config\RectorConfig;
 use Rector\Php53\Rector\Ternary\TernaryToElvisRector;
 use Rector\Php80\Rector\Class_\ClassPropertyAssignToConstructorPromotionRector;
@@ -38,6 +39,7 @@
     // DTOs looks a bit ugly with this, lets consider if we want this
     ->withSkip([
         ClassPropertyAssignToConstructorPromotionRector::class,
+        FlipTypeControlToUseExclusiveTypeRector::class,
         // this is conflicting with our phpstan rules - either they should change or this needs to be skipped
         TernaryToElvisRector::class,
     ])
diff --git a/src/SIE/Data/Transaction.php b/src/SIE/Data/Transaction.php
index fc20479..2660531 100644
--- a/src/SIE/Data/Transaction.php
+++ b/src/SIE/Data/Transaction.php
@@ -189,7 +189,7 @@ public function setRegistrationSign(string $registrationSign): self
      */
     public function validate(): void
     {
-        if (! $this->account instanceof Account) {
+        if ($this->account === null) {
             throw new DomainException('Mandatory field: account');
         }