diff --git a/src/compute_engines/summary_stats/summary_stats.cairo b/src/compute_engines/summary_stats/summary_stats.cairo
index 542f06dd..06c89640 100644
--- a/src/compute_engines/summary_stats/summary_stats.cairo
+++ b/src/compute_engines/summary_stats/summary_stats.cairo
@@ -78,6 +78,7 @@ mod SummaryStats {
             stop: u64,
             aggregation_mode: AggregationMode
         ) -> (u128, u32) {
+            assert(start < stop, 'start must be < stop');
             let oracle_address = self.oracle_address.read();
             let oracle_dispatcher = IOracleABIDispatcher { contract_address: oracle_address };
 
@@ -130,6 +131,7 @@ mod SummaryStats {
             num_samples: u64,
             aggregation_mode: AggregationMode,
         ) -> (u128, u32) {
+            assert(start_tick < end_tick, 'start_tick must be < end_tick');
             let oracle_address = self.oracle_address.read();
 
             assert(num_samples > 0, 'num_samples must be > 0');
@@ -140,7 +142,6 @@ mod SummaryStats {
                 .get_latest_checkpoint_index(data_type, aggregation_mode);
             let (_start_cp, start_index) = oracle_dispatcher
                 .get_last_checkpoint_before(data_type, start_tick, aggregation_mode);
-            let decimals = oracle_dispatcher.get_decimals(data_type);
 
             let mut end_index = 0;
             if (end_tick == 0) {
@@ -168,8 +169,8 @@ mod SummaryStats {
                 tick_arr.append(TickElem { tick: cp.timestamp, value: fixed_val });
                 idx += 1;
             };
-
-            (volatility(tick_arr.span()), decimals)
+            //the number of decimals is hardcoded to 8 by the volatilty computation in metrics.cairo
+            (volatility(tick_arr.span()), 8)
         }