diff --git a/code/controllers/subsystem/research.dm b/code/controllers/subsystem/research.dm
index 99f568998b..46fb232d6d 100644
--- a/code/controllers/subsystem/research.dm
+++ b/code/controllers/subsystem/research.dm
@@ -346,12 +346,12 @@ SUBSYSTEM_DEF(research)
 		for(var/i in bitcoins)
 			bitcoins[i] *= income_time_difference / 10
 		science_tech.add_point_list(bitcoins)
-		if(!length(last_bitcoins))
-			last_bitcoins = science_tech.research_points
-		for(var/i in last_bitcoins)
-			var/old_weighted = last_bitcoins[i] * (1 MINUTES - income_time_difference)
+		if(!length(science_tech.last_bitcoins))
+			science_tech.last_bitcoins = science_tech.research_points
+		for(var/i in science_tech.last_bitcoins)
+			var/old_weighted = science_tech.last_bitcoins[i] * (1 MINUTES - income_time_difference)
 			var/new_weighted = science_tech.research_points[i] * income_time_difference
-			last_bitcoins[i] = round((old_weighted + new_weighted) / (1 MINUTES))
+			science_tech.last_bitcoins[i] = round((old_weighted + new_weighted) / (1 MINUTES))
 	last_income = world.time
 
 /datum/controller/subsystem/research/proc/calculate_server_coefficient()	//Diminishing returns.