diff --git a/src/dbshow.c b/src/dbshow.c
index 7b5e451..78cb4cb 100644
--- a/src/dbshow.c
+++ b/src/dbshow.c
@@ -869,7 +869,6 @@ void showhours(const interfaceinfo *interface)
 	timeused_debug(__func__, 0);
 }
 
-// TODO: alert needs new function due to different format
 // TODO: image? output below doesn't have much graphics potential, line in 5 minute graph could be one alternative
 // TODO: tests
 void show95thpercentile(const interfaceinfo *interface)
diff --git a/src/percentile.c b/src/percentile.c
index dcc6063..fa360b3 100644
--- a/src/percentile.c
+++ b/src/percentile.c
@@ -2,6 +2,7 @@
 #include "dbsql.h"
 #include "percentile.h"
 
+// TODO: tests
 int getpercentiledata(percentiledata *pdata, const char *iface)
 {
 	uint32_t entry = 0, entrylimit;
diff --git a/src/vnstat_func.c b/src/vnstat_func.c
index e14cb56..7b0487e 100644
--- a/src/vnstat_func.c
+++ b/src/vnstat_func.c
@@ -685,7 +685,7 @@ int parsealertargs(PARAMS *p, char **argv)
 	currentarg++;
 
 	if (p->alerttype == AT_Percentile && (p->alertoutput == 2 || p->alertexit == 2)) {
-		printf("Error: Estimate conditions cannot be used in combination with selected alert type.\n");
+		printf("Error: Estimate output and exit conditions cannot be used in combination with selected alert type.\n");
 		showalerthelp();
 		return 0;
 	}
@@ -721,6 +721,12 @@ int parsealertargs(PARAMS *p, char **argv)
 		return 0;
 	}
 
+	if (p->alerttype == AT_Percentile && (p->alertcondition == AC_RX_Estimate || p->alertcondition == AC_TX_Estimate || p->alertcondition == AC_Total_Estimate)) {
+		printf("Error: Estimate conditions cannot be used in combination with selected alert type.\n");
+		showalerthelp();
+		return 0;
+	}
+
 	// limit
 	if (!isnumeric(argv[currentarg])) {
 		printf("Error: Limit parameter for %s must be a greater than zero integer without decimals.\n", argv[0]);